diff --git a/src/emacs/lean-syntax.el b/src/emacs/lean-syntax.el
index 2057c63a3..651ae94b7 100644
--- a/src/emacs/lean-syntax.el
+++ b/src/emacs/lean-syntax.el
@@ -72,7 +72,7 @@
            (zero-or-more (or whitespace "{" "["))
            (group (zero-or-more (not whitespace))))
       (2 'font-lock-function-name-face))
-     ("\\(set_opaque\\|set_option\\)[ \t]*\\([^ \t\n]*\\)" (2 'font-lock-constant-face))
+     ("\\(set_option\\)[ \t]*\\([^ \t\n]*\\)" (2 'font-lock-constant-face))
      ;; place holder
      (,(rx symbol-start "_" symbol-end) . 'font-lock-preprocessor-face)
      ;; sorry