know one's ass from a hole in the ground

== English == === Alternative forms === know the difference between one's ass and a hole in the ground === Verb === know one's ass from a hole in the ground (third-person singular simple present knows one's ass from a hole in the ground, present participle knowing one's ass from a hole in the ground, simple past knew one's ass from a hole in the ground, past participle known one's ass from a hole in the ground) (idiomatic, vulgar) To have an adequate level of knowledge or skill; to understand what one is doing or talking about. ==== Usage notes ==== Almost always used in negative constructions to describe someone's ignorance or stupidity, such as: He doesn't know his ass from a hole in the ground. ==== Synonyms ==== find one's ass with both hands and a flashlight (archaic) know B from a battledore know one's ass from one's elbow know one's head from a hole in the ground know one's head from one's ass know shit from Shinola know what one is about know which end is up ==== Antonyms ==== See know one's stuff ==== Related terms ==== know someone from a hole in the ground ==== Translations ====