be one card cards short of a full deck

be one card/several cards short of a full deck

(humorous)

if someone is one card short of a full deck, they are stupid or crazy Do you think your cousin might be one card short of a full deck?

Name	Pronounced	Usage
Caroline	ka-ro-LEEN (French), KER-ə-lien (English), KER-ə-lin (English), KAR-ə-lien (English), KAR-ə-lin (English)	French, English, German, Swedish, Norwegian, Danish, Dutch
Evaline	-	English
Avila	-	Ancient Germanic
Creighton	KRAY-tən	English (Rare)
KlytiË	-	Greek Mythology
Hilargi	-	Basque