polemic vs contestation

polemic and contestation both are nouns.

Word	Noun	Adjective	Verb	Adverb
polemic	Yes	Yes	No	No
contestation	Yes	No	No	No

As nouns, contestation is a hypernym of polemic; that is, contestation is a word with a broader meaning than polemic:

polemic: a controversy (especially over a belief or dogma)
contestation: a contentious speech act; a dispute where there is strong disagreement

Other hypernyms of polemic include arguing, argument, contention, controversy, disceptation, disputation, tilt.

polemic (noun)	contestation (noun)
a controversy (especially over a belief or dogma)	a contentious speech act; a dispute where there is strong disagreement
a writer who argues in opposition to others (especially in theology)

polemic (adjective)	contestation (adjective)
of or involving dispute or controversy