sport jacket vs sports coat

sport jacket and sports coat both are nouns.

Word	Noun	Adjective	Verb	Adverb
sport jacket	Yes	No	No	No
sports coat	Yes	No	No	No

As nouns, sport jacket and sports coat are synonyms defined as:

sport jacket and sports coat: lightweight single-breasted jacket; often striped in the colors of a club or school

Other synonyms of sport jacket include blazer, sport coat, sports jacket.

sport jacket (noun)	sports coat (noun)
lightweight single-breasted jacket; often striped in the colors of a club or school	lightweight single-breasted jacket; often striped in the colors of a club or school