gaoler vs jailer

gaoler and jailer both are nouns.

Word	Noun	Adjective	Verb	Adverb
gaoler	Yes	No	No	No
jailer	Yes	No	No	No

As nouns, gaoler and jailer are synonyms defined as:

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

gaoler (noun)	jailer (noun)
someone who guards prisoners	someone who guards prisoners