backstop vs infielder

backstop and infielder both are nouns.

Word	Noun	Adjective	Verb	Adverb
backstop	Yes	No	Yes	No
infielder	Yes	No	No	No

As nouns, infielder is a hypernym of backstop; that is, infielder is a word with a broader meaning than backstop:

backstop (noun)	infielder (noun)
a precaution in case of an emergency	(baseball) a person who plays a position in the infield
(baseball) a fence or screen (as behind home plate) to prevent the ball from traveling out of the playing field
(baseball) the person who plays the position of catcher

backstop (verb)	infielder (verb)
act as a backstop