coat vs overgarment

coat and overgarment both are nouns.

Word	Noun	Adjective	Verb	Adverb
coat	Yes	No	Yes	No
overgarment	Yes	No	No	No

As nouns, overgarment is a hypernym of coat; that is, overgarment is a word with a broader meaning than coat:

coat: an outer garment that has sleeves and covers the body from shoulder down; worn outdoors
overgarment: a garment worn over other garments

Other hypernyms of coat include outer garment.

coat (noun)	overgarment (noun)
growth of hair or wool or fur covering the body of an animal	a garment worn over other garments
an outer garment that has sleeves and covers the body from shoulder down; worn outdoors
a thin layer covering something

coat (verb)	overgarment (verb)
cover or provide with a coat
put a coat on; cover the surface of; furnish with a surface
form a coat over