not know your arse from your elbow是什么意思

词组 not know your arse from your elbow 释义 ●not know your arse from your elbow (BrE) (NAmE not know your ass from your elbow) (⚠, slang) be very stupid or completely lacking in skill 愚蠢之极；屁都不懂◆Don’t ask him to organize things! He doesn’t...