shut up vs lock up

shut up is an adjective but lock up is not an adjective.

Word	Noun	Adjective	Verb	Adverb
shut up	No	Yes	Yes	No
lock up	No	No	Yes	No

As verbs, shut up and lock up are synonyms defined as:

shut up and lock up: place in a place where something cannot be removed or someone cannot escape

Other synonyms of shut up include lock, lock away, lock in, put away, shut away.

shut up (adjective)	lock up (adjective)
closely confined

shut up (verb)	lock up (verb)
cause to be quiet or not talk	place in a place where something cannot be removed or someone cannot escape
refuse to talk or stop talking; fall silent	secure by locking
place in a place where something cannot be removed or someone cannot escape