know shit from Shinola

and tell shit from Shinola

Fig. Inf. to know what's what; to be intelligent and aware. (Always in the negative. Shinola is a brand of shoe polish. A person who doesn't know shit from Shinola is very stupid.) Poor Tom doesn't know shit from Shinola. Fred can't tell shit from Shinola, and he's been made my boss. know someone as someone to know someone by a different name. I know her as Candy La Tour. She has been known as Mary Rogers since her marriage.

know shit from Shinola

and tell shit from Shinola (...ʃɑɪˈnolə)

tv. to know what’s what; to be intelligent and aware. (see also No Shinola!.) Poor Tom doesn’t know shit from Shinola.