be one card shy of a (full) deck

To be not very intelligent or of questionable mental capacity. This expression can appear in many different forms and variations (e.g., "a few sandwiches short of a picnic," "one brick short of a load.," etc.). He says he's going to start a business selling bees as pets—I think he may be one card shy of a full deck. The new manager is nice enough, but he's one card shy of a deck, if you ask me.

Common Names:

Name	Pronounced	Usage
Emiliya	-	Bulgarian
Natanaele	-	Italian
Deepak	-	Indian, Hindi, Marathi, Bengali, Gujarati, Punjabi, Malayalam, Kannada, Tamil, Telugu, Nepali
Leonardo	le-o-NAHR-do (Italian, Spanish), lee-ə-NAHR-do (English)	Italian, Spanish, Portuguese, History
Alvin	AL-vin	English
Jacqueline	zha-kə-LEEN (French), zhak-LEEN (French), JAK-ə-leen (English), JAK-ə-lin (English)	French, English