know-nothing (adjective) empty-headed: flighty, scatterbrained
Sinonime: accurate, acid,
acute, barbed, boiled down, calling a spade a spade,
cutting, in a nutshell,
incisive, insinuating,
keen, laid on the line,
legit, meaty, on the button, on the nose,
pertinent,
pregnant, right to it, right-on,
sarcastic,
sharp, short-and-sweet,
tart,
telling, trenchant
Antonime: calming,
mild,
nice,
soothing