'shut up' definitions:

Definition of 'shut up'

From: WordNet
adjective
Closely confined [syn: pent, shut up(p)]
verb
Refuse to talk or stop talking; fall silent; "The children shut up when their father approached" [syn: close up, clam up, dummy up, shut up, belt up, button up, be quiet, keep mum] [ant: open up]
verb
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" [syn: lock in, lock away, lock, put away, shut up, shut away, lock up]
verb
Cause to be quiet or not talk; "Please silence the children in the church!" [syn: hush, quieten, silence, still, shut up, hush up] [ant: louden]

Synonyms of 'shut up'

From: Moby Thesaurus