oft vs oftentimes

oft and oftentimes both are adverbs.

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

As adverbs, oft and oftentimes are synonyms defined as:

Other synonyms of oft include frequently, often, ofttimes.

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