batter vs pinch hitter

batter and pinch hitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
batter	Yes	No	Yes	No
pinch hitter	Yes	No	No	No

As nouns, pinch hitter is a hyponym of batter; that is, pinch hitter is a word with a more specific, narrower meaning than batter:

Other hyponyms of batter include bunter, designated hitter, switch-hitter, whiffer.

batter (noun)	pinch hitter (noun)
a liquid or semiliquid mixture, as of flour, eggs, and milk, used in cooking	(baseball) a substitute for the regular batter
(baseball) a ballplayer who is batting

batter (verb)	pinch hitter (verb)
make a dent or impression in
strike violently and repeatedly
strike against forcefully