gum vs sweet gum

gum and sweet gum both are nouns.

Word	Noun	Adjective	Verb	Adverb
gum	Yes	No	Yes	No
sweet gum	Yes	No	No	No

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

gum: wood or lumber from any of various gum trees especially the sweet gum
sweet gum: reddish-brown wood and lumber from heartwood of the sweet gum tree used to make furniture

Other hyponyms of gum include hazelwood, red gum, satin walnut.

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

gum: any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying
sweet gum: aromatic exudate from the sweet gum tree

gum (noun)	sweet gum (noun)
the tissue (covered by mucous membrane) of the jaws that surrounds the bases of the teeth	a North American tree of the genus Liquidambar having prickly spherical fruit clusters and fragrant sap
a preparation (usually made of sweetened chicle) for chewing	aromatic exudate from the sweet gum tree
any of various trees of the genera Eucalyptus or Liquidambar or Nyssa that are sources of gum	reddish-brown wood and lumber from heartwood of the sweet gum tree used to make furniture
wood or lumber from any of various gum trees especially the sweet gum
any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying
cement consisting of a sticky substance that is used as an adhesive

gum (verb)	sweet gum (verb)
exude or form gum
become sticky
grind with the gums; chew without teeth and with great difficulty
cover, fill, fix or smear with or as if with gum