pantomime vs playact

pantomime is a noun but playact is not a noun.

Word	Noun	Adjective	Verb	Adverb
pantomime	Yes	No	Yes	No
playact	No	No	Yes	No

As verbs, playact is a hypernym of pantomime; that is, playact is a word with a broader meaning than pantomime:

pantomime: act out without words but with gestures and bodily movements only
playact: perform on a stage or theater

Other hypernyms of pantomime include act, play, roleplay.

pantomime (noun)	playact (noun)
a performance using gestures and body movements without words

pantomime (verb)	playact (verb)
act out without words but with gestures and bodily movements only	perform on a stage or theater