mastic vs shrub

mastic and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
mastic	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of mastic; that is, shrub is a word with a broader meaning than mastic:

mastic: an evergreen shrub of the Mediterranean region that is cultivated for its resin
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of mastic include bush.

mastic (noun)	shrub (noun)
an evergreen shrub of the Mediterranean region that is cultivated for its resin	a low woody perennial plant usually having several major stems
an aromatic exudate from the mastic tree; used chiefly in varnishes
a pasty cement used as an adhesive or filler