two-base hit vs two-baser

two-base hit and two-baser both are nouns.

Word	Noun	Adjective	Verb	Adverb
two-base hit	Yes	No	No	No
two-baser	Yes	No	No	No

As nouns, two-base hit and two-baser are synonyms defined as:

two-base hit and two-baser: a base hit on which the batter stops safely at second base

Other synonyms of two-base hit include double, two-bagger.

two-base hit (noun)	two-baser (noun)
a base hit on which the batter stops safely at second base	a base hit on which the batter stops safely at second base