effort vs elbow grease

effort and elbow grease both are nouns.

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

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

Other synonyms of effort include exertion, sweat, travail.

effort (noun)	elbow grease (noun)
earnest and conscientious activity intended to do or accomplish something	use of physical or mental energy; hard work
use of physical or mental energy; hard work
a notable achievement
a series of actions advancing a principle or tending toward a particular end