lamentation vs mourning

lamentation and mourning both are nouns.

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

As nouns, lamentation and mourning are synonyms defined as:

lamentation and mourning: the passionate and demonstrative activity of expressing grief

lamentation (noun)	mourning (noun)
the passionate and demonstrative activity of expressing grief	the passionate and demonstrative activity of expressing grief
a cry of sorrow and grief	state of sorrow over the death or departure of a loved one

lamentation (adjective)	mourning (adjective)
	sorrowful through loss or deprivation