doesn't/wouldn't know (one's) ass from (one's) elbow(redirected from know ass from elbow)
Note: This page may contain terms or definitions that are offensive or inappropriate for some readers.
doesn't/wouldn't know (one's) ass from (one's) elbow
rude slang Is very stupid or dimwitted. I'm not surprised to hear that she got lost two blocks away from her house—she doesn't know her ass from her elbow.