ofttimes vs frequently

ofttimes and frequently both are adverbs.

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

As adverbs, ofttimes and frequently are synonyms defined as:

Other synonyms of ofttimes include oft, often, oftentimes.

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