lamenting vs wailing

lamenting is not a noun while wailing is a noun.

Word	Noun	Adjective	Verb	Adverb
lamenting	No	Yes	No	No
wailing	Yes	Yes	No	No

As adjectives, lamenting and wailing are synonyms defined as:

lamenting and wailing: vocally expressing grief or sorrow or resembling such expression

Other synonyms of lamenting include wailful.

lamenting (noun)	wailing (noun)
	loud cries made while weeping

lamenting (adjective)	wailing (adjective)
vocally expressing grief or sorrow or resembling such expression	vocally expressing grief or sorrow or resembling such expression