diff --git a/examples/webpmux.c b/examples/webpmux.c
index ce6bdfe3..38637642 100644
--- a/examples/webpmux.c
+++ b/examples/webpmux.c
@@ -472,11 +472,11 @@ static WebPMux* DuplicateMuxHeader(const WebPMux* const mux) {
 }
 
 static int ParseFrameArgs(const char* args, WebPMuxFrameInfo* const info) {
-  int dispose_method, dummy;
+  int dispose_method, unused;
   char plus_minus, blend_method;
   const int num_args = sscanf(args, "+%d+%d+%d+%d%c%c+%d", &info->duration,
                               &info->x_offset, &info->y_offset, &dispose_method,
-                              &plus_minus, &blend_method, &dummy);
+                              &plus_minus, &blend_method, &unused);
   switch (num_args) {
     case 1:
       info->x_offset = info->y_offset = 0;  // fall through
diff --git a/imageio/image_enc.c b/imageio/image_enc.c
index fccb92bf..5a78cbda 100644
--- a/imageio/image_enc.c
+++ b/imageio/image_enc.c
@@ -155,8 +155,8 @@ int WebPWritePNG(const char* out_file_name, int use_stdout,
 }
 
 #elif defined(WEBP_HAVE_PNG)    // !HAVE_WINCODEC_H
-static void PNGAPI PNGErrorFunction(png_structp png, png_const_charp dummy) {
-  (void)dummy;  // remove variable-unused warning
+static void PNGAPI PNGErrorFunction(png_structp png, png_const_charp unused) {
+  (void)unused;  // remove variable-unused warning
   longjmp(png_jmpbuf(png), 1);
 }
 
@@ -320,7 +320,7 @@ int WebPWriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
   PutLE16(bmp_header + 26, 1);                    // number of planes
   PutLE16(bmp_header + 28, bytes_per_px * 8);     // bits per pixel
   PutLE32(bmp_header + 30, 0);                    // no compression (BI_RGB)
-  PutLE32(bmp_header + 34, 0);                    // image size (dummy)
+  PutLE32(bmp_header + 34, 0);                    // image size (placeholder)
   PutLE32(bmp_header + 38, 2400);                 // x pixels/meter
   PutLE32(bmp_header + 42, 2400);                 // y pixels/meter
   PutLE32(bmp_header + 46, 0);                    // number of palette colors
diff --git a/src/dsp/cpu.c b/src/dsp/cpu.c
index 4ca90d88..dac67c5d 100644
--- a/src/dsp/cpu.c
+++ b/src/dsp/cpu.c
@@ -210,8 +210,9 @@ static int wasmCPUInfo(CPUFeature feature) {
 }
 VP8CPUInfo VP8GetCPUInfo = wasmCPUInfo;
 #elif defined(WEBP_USE_NEON)
-// define a dummy function to enable turning off NEON at runtime by setting
-// VP8DecGetCPUInfo = NULL
+// In most cases this function doesn't check for NEON support (it's assumed by
+// the configuration), but enables turning off NEON at runtime, for testing
+// purposes, by setting VP8DecGetCPUInfo = NULL.
 static int armCPUInfo(CPUFeature feature) {
   if (feature != kNEON) return 0;
 #if defined(__linux__) && defined(WEBP_HAVE_NEON_RTCD)
diff --git a/src/enc/alpha_enc.c b/src/enc/alpha_enc.c
index dce9ca95..13f6ec89 100644
--- a/src/enc/alpha_enc.c
+++ b/src/enc/alpha_enc.c
@@ -361,7 +361,7 @@ static int EncodeAlpha(VP8Encoder* const enc,
 //------------------------------------------------------------------------------
 // Main calls
 
-static int CompressAlphaJob(void* arg1, void* dummy) {
+static int CompressAlphaJob(void* arg1, void* unused) {
   VP8Encoder* const enc = (VP8Encoder*)arg1;
   const WebPConfig* config = enc->config_;
   uint8_t* alpha_data = NULL;
@@ -381,7 +381,7 @@ static int CompressAlphaJob(void* arg1, void* dummy) {
   }
   enc->alpha_data_size_ = (uint32_t)alpha_size;
   enc->alpha_data_ = alpha_data;
-  (void)dummy;
+  (void)unused;
   return 1;
 }
 
diff --git a/swig/libwebp_python_wrap.c b/swig/libwebp_python_wrap.c
index 10555738..3aa27285 100644
--- a/swig/libwebp_python_wrap.c
+++ b/swig/libwebp_python_wrap.c
@@ -2764,7 +2764,7 @@ SWIG_Python_DestroyModule(void *vptr)
 SWIGRUNTIME void
 SWIG_Python_SetModule(swig_module_info *swig_module) {
 #if PY_VERSION_HEX >= 0x03000000
- /* Add a dummy module object into sys.modules */
+ /* Add a placeholder module object into sys.modules */
   PyObject *module = PyImport_AddModule((char*)"swig_runtime_data" SWIG_RUNTIME_VERSION);
 #else
   static PyMethodDef swig_empty_runtime_method_table[] = { {NULL, NULL, 0, NULL} }; /* Sentinel */