prison guard vs jailer

prison guard and jailer both are nouns.

Word	Noun	Adjective	Verb	Adverb
prison guard	Yes	No	No	No
jailer	Yes	No	No	No

As nouns, prison guard and jailer are synonyms defined as:

Other synonyms of prison guard include gaoler, jailor, screw, turnkey.

prison guard (noun)	jailer (noun)
someone who guards prisoners	someone who guards prisoners