gag vs quieten

gag is a noun but quieten is not a noun.

Word	Noun	Adjective	Verb	Adverb
gag	Yes	No	Yes	No
quieten	No	No	Yes	No

As verbs, quieten is a hypernym of gag; that is, quieten is a word with a broader meaning than gag:

Other hypernyms of gag include hush, hush up, shut up, silence, still.

gag (noun)	quieten (noun)
restraint put into a person's mouth to prevent speaking or shouting
a humorous anecdote or remark intended to provoke laughter

gag (verb)	quieten (verb)
struggle for breath; have insufficient oxygen intake	cause to be quiet or not talk
make an unsuccessful effort to vomit; strain to vomit	make calm or still
cause to retch or choke	become quiet or quieter
make jokes or quips
be too tight; rub or press
tie a gag around someone's mouth in order to silence them
prevent from speaking out