guts vs grit

guts and grit both are nouns.

Word	Noun	Adjective	Verb	Adverb
guts	Yes	No	No	No
grit	Yes	No	Yes	No

As nouns, guts and grit are synonyms defined as:

Other synonyms of guts include backbone, gumption, moxie, sand.

guts (noun)	grit (noun)
fortitude and determination	fortitude and determination
	a hard coarse-grained siliceous sandstone

guts (verb)	grit (verb)
	clench together
	cover with a grit