elisp undef

(defun undef--verify (msg sym)
  "Make sure the symbol should be unbound."
  (when (symbolp sym)
    (intern-soft (read-string (concat msg " ") (symbol-name sym)))))

(defun undef-variable (&optional sym)
  "Unbind the variable of the supllied symbol or the symbol at the point."
  (interactive (list (undef--verify "Unbind variable:" (symbol-at-point))))
  (when (symbolp sym)
    (makunbound sym)))

(defun undef-function (&optional sym)
  "Unbind the function of the supllied symbol or the symbol at the point."
  (interactive (list (undef--verify "Unbind variable:" (symbol-at-point))))
  (when (symbolp sym)
    (fmakunbound sym)))

(defun undef-symbol (&optional sym)
  "Unintern the supllied symbol or the symbol at the point."
  (interactive (list (undef--verify "Unbind variable:" (symbol-at-point))))
  (when (symbolp sym)
    (unintern sym obarray)))

;; Suggested key bindings.
(global-set-key (kbd "C-c u v") #'undef-variable)
(global-set-key (kbd "C-c u f") #'undef-function)
(global-set-key (kbd "C-c u s") #'undef-symbol)