happy-go-lucky vs carefree

happy-go-lucky and carefree both are adjectives.

Word	Noun	Adjective	Verb	Adverb
happy-go-lucky	No	Yes	No	No
carefree	No	Yes	No	No

As adjectives, happy-go-lucky and carefree are synonyms defined as:

Other synonyms of happy-go-lucky include devil-may-care, freewheeling, harum-scarum, slaphappy.

happy-go-lucky (adjective)	carefree (adjective)
cheerfully irresponsible	cheerfully irresponsible
	free of trouble and worry and care