diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 3d5d5b59..3226b246 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -447,7 +447,6 @@ Forth:
   lexer: Text only
   extensions:
   - .4th
-  - .fth
 
 GAS:
   type: programming