sportfishing vs fishing

sportfishing and fishing both are nouns.

Word	Noun	Adjective	Verb	Adverb
sportfishing	Yes	No	No	No
fishing	Yes	No	No	No

As nouns, sportfishing and fishing are synonyms defined as:

sportfishing (noun)	fishing (noun)
the act of someone who fishes as a diversion	the act of someone who fishes as a diversion
	the occupation of catching fish for a living