# he's not playing with a full deck

idiom · CEFR B1

Source: https://englishreference.com/idiom/hes-not-playing-with-a-full-deck
Updated: 2026-06-07

## Meaning

He's dumb

## Examples

- He thinks the sun is a planet; he's not playing with a full deck.
- After he tried to wash his laptop with soap and water, everyone realized he's not playing with a full deck.
- The neighbors often whisper that the old man is not playing with a full deck because he spends every afternoon trying to teach his cat how to speak French.

## Origin

20th-century American slang: a card game played with cards missing can't be played properly. (disputed)

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.