button up vs be quiet

button up and be quiet both are verbs.

Word	Noun	Adjective	Verb	Adverb
button up	No	No	Yes	No
be quiet	No	No	Yes	No

As verbs, button up and be quiet are synonyms defined as:

Other synonyms of button up include belt up, clam up, close up, dummy up, keep mum, shut up.

button up (verb)	be quiet (verb)
refuse to talk or stop talking; fall silent	refuse to talk or stop talking; fall silent