1. close up, clam up, dummy up, shut up, belt up, button up, be quiet, keep mum
usage: refuse to talk or stop talking; fall silent; "The children shut up when their father approached"
2. lock in, lock away, lock, put away, shut up, shut away, lock up, confine
usage: place in a place where something cannot be removed or someone cannot escape; "The parents locked her daughter up for the weekend"; "She locked her jewels in the safe"