(entered for 01.04.06)

Meaning: mentally deficient. Use examples.
Rewrite 1: working short a tool or two
Rewrite 2: shuffling with only half a deck
Rewrite 3: walking on legs with no feet
Rewrite 4: powered by half a battery

Comment: You can have a lot of fun with this one, imagining all the ways someone could be working without a full deck.

More reading about clichés
What I found when I googled “clichés”:
• Statistical Modeling: “Seven statistical clichés used by baseball announcers.”