kvetch vs lament

kvetch and lament both are nouns.

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

As verbs, lament is a hyponym of kvetch; that is, lament is a word with a more specific, narrower meaning than kvetch:

kvetch (noun)	lament (noun)
(Yiddish) a nagging complaint	a mournful poem; a lament for the dead
(Yiddish) a constant complainer	a song or hymn of mourning composed or performed as a memorial to a dead person
	a cry of sorrow and grief

kvetch (verb)	lament (verb)
express complaints, discontent, displeasure, or unhappiness	regret strongly
	express grief verbally