A few fries short of a Happy Meal

Meaning

This is a humorous and slightly insulting way to say someone is not very bright or is acting foolishly. It implies the person is missing some mental components.

Sarcastic, teasing

Used in a sentence

• He tried to plug the toaster into the lamp, I think he is a few fries short of a Happy Meal.
• Do not ask him for directions, he is a few fries short of a Happy Meal.
• She is a sweet lady, but definitely a few fries short of a Happy Meal.