pull a face vs mop

pull a face is not a noun while mop is a noun.

Word	Noun	Adjective	Verb	Adverb
pull a face	No	No	Yes	No
mop	Yes	No	Yes	No

As verbs, mop is a hyponym of pull a face; that is, mop is a word with a more specific, narrower meaning than pull a face:

pull a face: contort the face to indicate a certain mental or emotional state
mop: make a sad face and thrust out one's lower lip

Other hyponyms of pull a face include squinch, squint, wince, smile, frown, glower, lour, lower, screw up, mow, pout.

pull a face (noun)	mop (noun)
	cleaning implement consisting of absorbent material fastened to a handle; for cleaning floors

pull a face (verb)	mop (verb)
contort the face to indicate a certain mental or emotional state	make a sad face and thrust out one's lower lip
	to wash or wipe with or as if with a mop