Remap C-w to backward-kill-word if the region isn't active

init.el

@@ -568,7 +568,8 @@
            attempt-orderly-shutdown-on-fatal-signal nil
            find-function-C-source-directory (acdw/find-emacs-source))
 
-  (:global "M-=" count-words)
+  (:global "M-=" count-words
+           "C-w" acdw/kill-region-or-backward-word)
 
   ;; Remap C-h to DEL -- <f1> can be the "help" key
   (define-key key-translation-map [?\C-h] [?\C-?])

lisp/acdw.el

@@ -29,6 +29,8 @@
 
 
 ;;; Utility functions
+;; I don't prefix these because ... reasons.  Honestly I probably should prefix
+;; them.
 
 (defun dos2unix (buffer)
   "Replace \r\n with \n in BUFFER."
@@ -58,6 +60,13 @@ each hook in HOOKS."
        ,@(dolist (hook hook-list hook-defun-add-hook-list)
            (push `(add-hook ',hook #',func-name) hook-defun-add-hook-list)))))
 
+(defun kill-region-or-backward-word (arg)
+  "Kill region if active, or backward word if not."
+  (interactive "p")
+  (if (region-active-p)
+      (kill-region (region-beginning) (region-end))
+    (backward-kill-word arg)))
+
 (defmacro when-unfocused (name &rest forms)
   "Define a function NAME, executing FORMS, that fires when Emacs
 is unfocused."