Not know (one's) ass from a hole in the ground slang rude
To be extremely stupid; not to be alert
She didn't know her ass from a hole in the ground when quitting such a decent job.
What! You refused such a good price! You don't know your ass from a hole in the ground.
To have no money
Extremely stupid
Very stupid, or silly
Used to describe someone who is naive, gullible, inexperienced, easily fooled, ignorant, unsophisticated, etc.
To say, or believe something or someone that seems completely crazy, delusional, or stupid
The origin of this slang is not clear.
Friendships will develop well and be successful when the friends respect each other's privacy.
You should respect your friend's privacy. A hedge between keeps friendship green.