coverall vs overall

coverall and overall both are nouns.

Word	Noun	Adjective	Verb	Adverb
coverall	Yes	No	No	No
overall	Yes	Yes	No	No

As nouns, overall is a hyponym of coverall; that is, overall is a word with a more specific, narrower meaning than coverall:

coverall: a loose-fitting protective garment that is worn over other clothing
overall: a loose protective coverall or smock worn over ordinary clothing for dirty work

Other hyponyms of coverall include dust coat, duster, gabardine, gaberdine, smock, jumper, boilers suit, boilersuit.

coverall (noun)	overall (noun)
a loose-fitting protective garment that is worn over other clothing	(usually plural) work clothing consisting of denim trousers (usually with a bib and shoulder straps)
	a loose protective coverall or smock worn over ordinary clothing for dirty work

coverall (adjective)	overall (adjective)
	involving only main features
	including everything