diff --git a/core/Dynamic.carp b/core/Dynamic.carp
index ccce54fe..b9dee77e 100644
--- a/core/Dynamic.carp
+++ b/core/Dynamic.carp
@@ -2,6 +2,12 @@
 
 (defmodule Dynamic
   ;; Functions for doing things at the REPL and during compile time.
+  (doc proc? "checks whether `x` is callable.")
+  (defndynamic proc? [x]
+    (or
+      (List.in? (dynamic-type x) '(fn closure))
+      (let [s (s-expr x)]
+        (and (not (empty? s)) (= 'dynamic (dynamic-type (car s)))))))
 
   (doc nil "is the value `nil`, i.e. the empty list.")
   (defdynamic nil '())