diff --git a/asm/assemble.c b/asm/assemble.c
index 10d9ec91..964efb0e 100644
--- a/asm/assemble.c
+++ b/asm/assemble.c
@@ -293,7 +293,7 @@ static const char *size_name(int size)
 
 static void warn_overflow(int size)
 {
-    nasm_warnf(ERR_PASS2 | WARN_NOV, "%s data exceeds bounds",
+    nasm_warnf(ERR_PASS2 | WARN_NUMBER_OVERFLOW, "%s data exceeds bounds",
                size_name(size));
 }
 
@@ -1674,7 +1674,7 @@ static void gencode(struct out_data *data, insn *ins)
                 nasm_nonfatal("non-absolute expression not permitted "
                               "as argument %d", c & 7);
             else if (opy->offset & ~mask)
-                nasm_warnf(ERR_PASS2 | WARN_NOV,
+                nasm_warnf(ERR_PASS2 | WARN_NUMBER_OVERFLOW,
                            "is4 argument exceeds bounds");
             c = opy->offset & mask;
             goto emit_is4;
@@ -1696,7 +1696,7 @@ static void gencode(struct out_data *data, insn *ins)
         case4(0254):
             if (absolute_op(opx) &&
                 (int32_t)opx->offset != (int64_t)opx->offset) {
-                nasm_warnf(ERR_PASS2 | WARN_NOV,
+                nasm_warnf(ERR_PASS2 | WARN_NUMBER_OVERFLOW,
                            "signed dword immediate exceeds bounds");
             }
             out_imm(data, opx, 4, OUT_SIGNED);
@@ -1766,7 +1766,7 @@ static void gencode(struct out_data *data, insn *ins)
                     /* If this wasn't explicitly byte-sized, warn as though we
                      * had fallen through to the imm16/32/64 case.
                      */
-                    nasm_warnf(ERR_PASS2 | WARN_NOV,
+                    nasm_warnf(ERR_PASS2 | WARN_NUMBER_OVERFLOW,
                                "%s value exceeds bounds",
                                (opx->type & BITS8) ? "signed byte" :
                                s == 16 ? "word" :
diff --git a/asm/float.c b/asm/float.c
index e857045b..6f26e678 100644
--- a/asm/float.c
+++ b/asm/float.c
@@ -232,7 +232,7 @@ static bool ieee_flconvert(const char *string, fp_limb *mant,
                     *p++ = *string - '0';
                 } else {
                     if (!warned) {
-                        nasm_warnf(WARN_FL_TOOLONG|ERR_PASS2,
+                        nasm_warnf(WARN_FLOAT_TOOLONG|ERR_PASS2,
                                    "floating-point constant significand contains "
                                    "more than %i digits", MANT_DIGITS);
                         warned = true;
@@ -799,7 +799,7 @@ static int to_float(const char *str, int s, uint8_t *result,
                 type = FL_NORMAL;
             } else if (exponent > 0) {
                 if (pass0 == 1)
-                    nasm_warnf(WARN_FL_OVERFLOW|ERR_PASS2,
+                    nasm_warnf(WARN_FLOAT_OVERFLOW|ERR_PASS2,
                                "overflow in floating-point constant");
                 type = FL_INFINITY;
             } else {
@@ -834,11 +834,11 @@ static int to_float(const char *str, int s, uint8_t *result,
         } else {
             if (daz || is_zero(mant)) {
                 /* Flush denormals to zero */
-                nasm_warnf(WARN_FL_UNDERFLOW|ERR_PASS2,
+                nasm_warnf(WARN_FLOAT_UNDERFLOW|ERR_PASS2,
                            "underflow in floating-point constant");
                 goto zero;
             } else
-                nasm_warnf(WARN_FL_DENORM|ERR_PASS2,
+                nasm_warnf(WARN_FLOAT_DENORM|ERR_PASS2,
                            "denormal floating-point constant");
         }
         break;
@@ -853,7 +853,7 @@ static int to_float(const char *str, int s, uint8_t *result,
             ieee_shr(mant, 1);
             exponent++;
             if (exponent >= (expmax << 1)-1) {
-                    nasm_warnf(WARN_FL_OVERFLOW|ERR_PASS2,
+                    nasm_warnf(WARN_FLOAT_OVERFLOW|ERR_PASS2,
                                "overflow in floating-point constant");
                 type = FL_INFINITY;
                 goto overflow;
diff --git a/asm/labels.c b/asm/labels.c
index 1152ba76..ead1f34b 100644
--- a/asm/labels.c
+++ b/asm/labels.c
@@ -517,14 +517,14 @@ void define_label(const char *label, int32_t segment,
         src_set(saved_line, saved_fname);
     } else if (changed && pass0 > 1 && lptr->defn.type != LBL_SPECIAL) {
         /*
-         * WARN_LABEL_LATE defaults to an error, as this should never actually happen.
+         * WARN_LABEL_REDEF_LATE defaults to an error, as this should never actually happen.
          * Just in case this is a backwards compatibility problem, still make it a
          * warning so that the user can suppress or demote it.
          *
          * As a special case, LBL_SPECIAL symbols are allowed to be changed
          * even during the last pass.
          */
-        nasm_warnf(WARN_LABEL_LATE,
+        nasm_warnf(WARN_LABEL_REDEF_LATE,
                    "label `%s' %s during code generation",
                    lptr->defn.label, created ? "defined" : "changed");
     }
diff --git a/asm/parser.c b/asm/parser.c
index dbfb11cb..04def6b4 100644
--- a/asm/parser.c
+++ b/asm/parser.c
@@ -463,7 +463,7 @@ restart_parse:
         if (i == ':') {         /* skip over the optional colon */
             i = stdscan(NULL, &tokval);
         } else if (i == 0) {
-            nasm_warnf(WARN_OL | ERR_PASS1,
+            nasm_warnf(WARN_ORPHAN_LABELS | ERR_PASS1,
                        "label alone on a line without a colon might be in error");
         }
         if (i != TOKEN_INSN || tokval.t_integer != I_EQU) {
diff --git a/asm/preproc.c b/asm/preproc.c
index 314a2013..af77e14b 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -2133,7 +2133,7 @@ static bool parse_mmacro_spec(Token *tline, MMacro *def, const char *directive)
 
     if (def->defaults && def->ndefs > def->nparam_max - def->nparam_min &&
         !def->plus)
-        nasm_warnf(ERR_PASS1|WARN_MDP, "too many default macro parameters in macro `%s'", def->name);
+        nasm_warnf(ERR_PASS1|WARN_MACRO_DEFAULTS, "too many default macro parameters in macro `%s'", def->name);
 
     return true;
 }
@@ -2966,7 +2966,7 @@ issue_error:
                               count, nasm_limit[LIMIT_REP]);
                 count = 0;
             } else if (count < 0) {
-                nasm_warnf(ERR_PASS2|WARN_NEG_REP,
+                nasm_warnf(ERR_PASS2|WARN_NEGATIVE_REP,
                            "negative `%%rep' count: %"PRId64, count);
                 count = 0;
             } else {
diff --git a/include/error.h b/include/error.h
index de07d45e..8d5084c8 100644
--- a/include/error.h
+++ b/include/error.h
@@ -104,15 +104,15 @@ static inline vefunc nasm_set_verror(vefunc ve)
 #define WARN_IDX(x)     	((x) >> WARN_SHR)
 
 #define WARN_MNP            	WARN( 1) /* macro-num-parameters warning */
-#define WARN_MSR            	WARN( 2) /* macro self-reference */
-#define WARN_MDP            	WARN( 3) /* macro default parameters check */
-#define WARN_OL             	WARN( 4) /* orphan label (no colon, and alone on line) */
-#define WARN_NOV            	WARN( 5) /* numeric overflow */
-#define WARN_GNUELF         	WARN( 6) /* using GNU ELF extensions */
-#define WARN_FL_OVERFLOW    	WARN( 7) /* FP overflow */
-#define WARN_FL_DENORM      	WARN( 8) /* FP denormal */
-#define WARN_FL_UNDERFLOW   	WARN( 9) /* FP underflow */
-#define WARN_FL_TOOLONG     	WARN(10) /* FP too many digits */
+#define WARN_MACRO_SELFREF            	WARN( 2) /* macro self-reference */
+#define WARN_MACRO_DEFAULTS            	WARN( 3) /* macro default parameters check */
+#define WARN_ORPHAN_LABELS             	WARN( 4) /* orphan label (no colon, and alone on line) */
+#define WARN_NUMBER_OVERFLOW            	WARN( 5) /* numeric overflow */
+#define WARN_GNU_ELF_EXTENSIONS         	WARN( 6) /* using GNU ELF extensions */
+#define WARN_FLOAT_OVERFLOW    	WARN( 7) /* FP overflow */
+#define WARN_FLOAT_DENORM      	WARN( 8) /* FP denormal */
+#define WARN_FLOAT_UNDERFLOW   	WARN( 9) /* FP underflow */
+#define WARN_FLOAT_TOOLONG     	WARN(10) /* FP too many digits */
 #define WARN_USER           	WARN(11) /* %warning directives */
 #define WARN_LOCK		WARN(12) /* bad LOCK prefixes */
 #define WARN_HLE		WARN(13) /* bad HLE prefixes */
@@ -121,12 +121,12 @@ static inline vefunc nasm_set_verror(vefunc ve)
 #define WARN_PTR		WARN(16) /* not a NASM keyword */
 #define WARN_BAD_PRAGMA		WARN(17) /* malformed pragma */
 #define WARN_UNKNOWN_PRAGMA	WARN(18) /* unknown pragma */
-#define WARN_NOTMY_PRAGMA	WARN(19) /* pragma inapplicable */
+#define WARN_NOT_MY_PRAGMA	WARN(19) /* pragma inapplicable */
 #define WARN_UNK_WARNING	WARN(20) /* unknown warning */
-#define WARN_NEG_REP		WARN(21) /* negative repeat count */
+#define WARN_NEGATIVE_REP		WARN(21) /* negative repeat count */
 #define WARN_PHASE		WARN(22) /* phase error in pass 1 */
 #define WARN_LABEL_REDEF	WARN(23) /* label redefined, but consistent */
-#define WARN_LABEL_LATE		WARN(24) /* label (re)defined during code generation */
+#define WARN_LABEL_REDEF_LATE		WARN(24) /* label (re)defined during code generation */
 
 /* These two should come last */
 #define WARN_ALL		(24+2) /* Do not use WARN() here */
diff --git a/nasmlib/readnum.c b/nasmlib/readnum.c
index 60d856e1..02e30830 100644
--- a/nasmlib/readnum.c
+++ b/nasmlib/readnum.c
@@ -164,7 +164,7 @@ int64_t readnum(const char *str, bool *error)
     }
 
     if (warn)
-        nasm_error(ERR_WARNING | ERR_PASS1 | WARN_NOV,
+        nasm_error(ERR_WARNING | ERR_PASS1 | WARN_NUMBER_OVERFLOW,
 		   "numeric constant %s does not fit in 64 bits",
 		   str);
 
diff --git a/output/outelf.c b/output/outelf.c
index 2ac8eb44..8270ba0b 100644
--- a/output/outelf.c
+++ b/output/outelf.c
@@ -919,7 +919,7 @@ static void elf32_out(int32_t segto, const void *data,
         }
 
         if (gnu16) {
-            nasm_warnf(WARN_GNUELF, "8- or 16-bit relocations "
+            nasm_warnf(WARN_GNU_ELF_EXTENSIONS, "8- or 16-bit relocations "
                        "in ELF32 is a GNU extension");
         } else if (asize != 4 && segment != NO_SEG) {
             nasm_nonfatal("Unsupported non-32-bit ELF relocation");
@@ -945,7 +945,7 @@ rel12adr:
                           " segment base references");
         } else {
             if (wrt == NO_SEG) {
-                nasm_warnf(WARN_GNUELF, "8- or 16-bit relocations "
+                nasm_warnf(WARN_GNU_ELF_EXTENSIONS, "8- or 16-bit relocations "
                            "in ELF is a GNU extension");
                 elf_add_reloc(s, segment, 0, reltype);
             } else {