part time vs part-time

part time and part-time both are adjectives.

Word	Noun	Adjective	Verb	Adverb
part time	No	Yes	No	No
part-time	No	Yes	No	Yes

As adjectives, part time and part-time are synonyms defined as:

part time and part-time: involving less than the standard or customary time for an activity

part time (adjective)	part-time (adjective)
involving less than the standard or customary time for an activity	involving less than the standard or customary time for an activity

part time (adverb)	part-time (adverb)
	for less than the standard number of hours