off-and-on vs fitful

off-and-on and fitful both are adjectives.

Word	Noun	Adjective	Verb	Adverb
off-and-on	No	Yes	No	No
fitful	No	Yes	No	No

As adjectives, off-and-on and fitful are synonyms defined as:

Other synonyms of off-and-on include interrupted.

off-and-on (adjective)	fitful (adjective)
intermittently stopping and starting	intermittently stopping and starting
	occurring in spells and often abruptly