exertion vs elbow grease

exertion and elbow grease both are nouns.

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

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

Other synonyms of exertion include effort, sweat, travail.

exertion (noun)	elbow grease (noun)
use of physical or mental energy; hard work	use of physical or mental energy; hard work