not very intelligent.

I could tell he was a few fries short of a Happy Meal, but unfortunately you can't arrest someone for being stupid.

Usage notes: this idiom appears in many different forms, including a few cards short of a full deck, a few bricks short of a full load, a few clowns short of a circus, and a few Cokes short of a six-pack, all with the same meaning

• put the squeeze on someone
• put the squeeze on something
• put the wind up
• put the wind up someone
• put thinking cap on
• put through
• put through hell
• put through hoops
• put through paces
• put through something
• put through their paces
• put through the mill
• put through the wringer
• put to bed
• put to death
• put too fine a point on it
• put to shame
• put to sleep
• put to the test
• put toward
• put toward something
• put two and two together
• put two and two together and get five
• put two and two together and make five
• put two cents in