overkill vs travail

overkill and travail both are nouns.

Word	Noun	Adjective	Verb	Adverb
overkill	Yes	No	No	No
travail	Yes	No	Yes	No

As nouns, travail is a hypernym of overkill; that is, travail is a word with a broader meaning than overkill:

overkill: any effort that seems to go farther than would be necessary to achieve its goal
travail: use of physical or mental energy; hard work

Other hypernyms of overkill include effort, elbow grease, exertion, sweat.

overkill (noun)	travail (noun)
any effort that seems to go farther than would be necessary to achieve its goal	use of physical or mental energy; hard work
the capability to obliterate a target with more weapons (especially nuclear weapons) than are required	concluding state of pregnancy; from the onset of contractions to the birth of a child

overkill (verb)	travail (verb)
	work hard