caseworker vs welfare worker

caseworker and welfare worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
caseworker	Yes	No	No	No
welfare worker	Yes	No	No	No

As nouns, caseworker and welfare worker are synonyms defined as:

caseworker and welfare worker: someone employed to provide social services (especially to the disadvantaged)

Other synonyms of caseworker include social worker.

caseworker (noun)	welfare worker (noun)
someone employed to provide social services (especially to the disadvantaged)	someone employed to provide social services (especially to the disadvantaged)