travail vs elbow grease

travail and elbow grease both are nouns.

Word	Noun	Adjective	Verb	Adverb
travail	Yes	No	Yes	No
elbow grease	Yes	No	No	No

As nouns, travail and elbow grease are synonyms defined as:

Other synonyms of travail include effort, exertion, sweat.

travail (noun)	elbow grease (noun)
use of physical or mental energy; hard work	use of physical or mental energy; hard work
concluding state of pregnancy; from the onset of contractions to the birth of a child

travail (verb)	elbow grease (verb)
work hard