Not Playing With A Full Deck Edit Meaning

1.

an expression used to indicate that a person isn't very smart

see also - not the brightest bulb on the porch, not the sharpest pencil in the drawer, a few bricks shy of a load,

Little Davey tried to iron his short & curlies (he's not playing with a full deck).

See idiot, dummy, stupid, shit-for-brains, brainless