WordNet sense 1 (place in a place where something cannot be removed or someone cannot escape):

lock, lock in, lock up, put away, lock away, shut away

WordNet sense 2 (refuse to talk or stop talking; fall silent):

close up, be quiet, belt up, button up, clam up, dummy up, keep mum

WordNet sense 3 (closely confined):

pent

WordNet sense 4 (not free to move about):

confined

WordNet sense 5 (cause to be quiet or not talk):

hush, silence, still, quieten, hush up