couldn't hit the side of a barn

slang Has very poor aim. Boy, you can't hit the broad side of a barn—the net is over here, you know! These guys haven't made a single basket in the last 10 minutes—they just can't hit the side of a barn right now.

A lousy shot. This useful phrase can be applied to baseball pitchers who can't get the ball over the plate, basketball players who miss free throws, golfers whose balls routinely go out of bounds, target shooters and archers who miss the target, and anyone else who can't get it right. Another similar farm-based expression is “couldn't hit a bull's ass with a barn shovel.”