lamentation vs lament

lamentation and lament both are nouns.

Word	Noun	Adjective	Verb	Adverb
lamentation	Yes	No	No	No
lament	Yes	No	Yes	No

As nouns, lamentation and lament are synonyms defined as:

Other synonyms of lamentation include plaint, wail.

lamentation (noun)	lament (noun)
the passionate and demonstrative activity of expressing grief	a mournful poem; a lament for the dead
a cry of sorrow and grief	a song or hymn of mourning composed or performed as a memorial to a dead person
	a cry of sorrow and grief

lamentation (verb)	lament (verb)
	regret strongly
	express grief verbally