Screw up

ERR

Think of a short word you might see on a computer screen when something goes wrong during data entry.

"Screw up" is a phrase that can mean to make a mistake, which directly points to the word "ERR"—a short way to say "error." The clue plays on the double meaning of "screw up," since "screw" can also refer to a fastener, but here it’s just a casual way to say "mess up." It’s a straightforward definition clue with no hidden wordplay, just a common expression leading to a concise three-letter answer.