oftentimes vs frequently

oftentimes and frequently both are adverbs.

Word	Noun	Adjective	Verb	Adverb
oftentimes	No	No	No	Yes
frequently	No	No	No	Yes

As adverbs, oftentimes and frequently are synonyms defined as:

Other synonyms of oftentimes include oft, often, ofttimes.

oftentimes (adverb)	frequently (adverb)
many times at short intervals	many times at short intervals