chew vs gumming

chew and gumming both are nouns.

Word	Noun	Adjective	Verb	Adverb
chew	Yes	No	Yes	No
gumming	Yes	No	No	No

As nouns, gumming is a hyponym of chew; that is, gumming is a word with a more specific, narrower meaning than chew:

chew: biting and grinding food in your mouth so it becomes soft enough to swallow
gumming: ineffectual chewing (as if without teeth)

Other hyponyms of chew include chomping, mumbling, rumination.

chew (noun)	gumming (noun)
biting and grinding food in your mouth so it becomes soft enough to swallow	ineffectual chewing (as if without teeth)
a wad of something chewable as tobacco

chew (verb)	gumming (verb)
chew (food); to bite and grind with the teeth