sport jacket vs sports jacket

sport jacket and sports jacket both are nouns.

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

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

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

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

sport jacket (noun)	sports jacket (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