nisus vs pains

nisus and pains both are nouns.

Word	Noun	Adjective	Verb	Adverb
nisus	Yes	No	No	No
pains	Yes	No	No	No

As nouns, nisus and pains are synonyms defined as:

Other synonyms of nisus include strain, striving.

nisus (noun)	pains (noun)
an effortful attempt to attain a goal	an effortful attempt to attain a goal