contention vs contestation

contention and contestation both are nouns.

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

As nouns, contention and contestation are synonyms defined as:

contention and contestation: a contentious speech act; a dispute where there is strong disagreement

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

contention (noun)	contestation (noun)
the act of competing as for profit or a prize	a contentious speech act; a dispute where there is strong disagreement
a contentious speech act; a dispute where there is strong disagreement
a point asserted as part of an argument