knock somebody down

Từ điển Oxford Advanced Learner 8th

▪ I. ˌknock sbˈdown/ˈover derived
to hit sb and make them fall to the ground
• She was knocked down by a bus.
• He knocked his opponent down three times in the first round.
Main entry: ↑knock_derived
 
▪ II. ˌknock sb ˈdown (from sth) (to sth) derived
(informal)to persuade sb to reduce the price of sth
•I managed to knock him down to $400.
Main entry: ↑knock_derived