oddball vs crackpot

oddball and crackpot both are nouns.

Word	Noun	Adjective	Verb	Adverb
oddball	Yes	No	No	No
crackpot	Yes	No	No	No

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

Other hyponyms of oddball include crank, fruitcake, nut, nut case, screwball, nutter, wacko, whacko.

oddball (noun)	crackpot (noun)
a person with an unusual or odd personality	a whimsically eccentric person