deviation vs variant

deviation and variant both are nouns.

Word	Noun	Adjective	Verb	Adverb
deviation	Yes	No	No	No
variant	Yes	Yes	No	No

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

Other hyponyms of deviation include discrepancy, variance, driftage, flection, flexion, inflection.

deviation (noun)	variant (noun)
deviate behavior	a variable quantity that is random
a turning aside (of your course or attention or concern)	something a little different from others of the same type
the error of a compass due to local magnetic disturbances	an event that departs from expectations
the difference between an observed value and the expected value of a variable or function	(biology) a group of organisms within a species that differ in trivial ways from similar groups
a variation that deviates from the standard or norm

deviation (adjective)	variant (adjective)
	differing from a norm or standard
	exhibiting variation and change