ball vs mothball

ball and mothball both are nouns.

Word	Noun	Adjective	Verb	Adverb
ball	Yes	No	Yes	No
mothball	Yes	No	Yes	No

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

ball: an object with a spherical shape
mothball: a small sphere of camphor or naphthalene used to keep moths away from stored clothing

Other hyponyms of ball include crystal ball, camphor ball, time-ball, fireball, fireball, globule, spherule, pellet, bolus.

ball (noun)	mothball (noun)
a pitch that is not in the strike zone	a small sphere of camphor or naphthalene used to keep moths away from stored clothing
a ball game played with a bat and ball between two teams of nine players; teams take turns at bat trying to score runs
round object that is hit or thrown or kicked in games
a spherical object used as a plaything
a solid projectile that is shot by a musket
a more or less rounded anatomical body or mass
one of the two male reproductive glands that produce spermatozoa and secrete androgens
a lavish dance requiring formal attire
a compact mass
an object with a spherical shape

ball (verb)	mothball (verb)
form into a ball by winding or rolling	put into long-term storage
to live very well