couldn't fight (one's) way out of a paper bag
Is extremely weak, ineffectual, or incompetent. You can definitely beat that scrawny kid—come on, he couldn't fight his way out of a paper bag! Don't assign that project to her, she couldn't fight her way out of a paper bag! A: "Did you hear that Sam got promoted to General Manager?" B: "You've got to be kidding me! That guy couldn't fight his way out of a paper bag!"
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.