devil-may-care vs happy-go-lucky

devil-may-care and happy-go-lucky both are adjectives.

Word	Noun	Adjective	Verb	Adverb
devil-may-care	No	Yes	No	No
happy-go-lucky	No	Yes	No	No

As adjectives, devil-may-care and happy-go-lucky are synonyms defined as:

Other synonyms of devil-may-care include carefree, freewheeling, harum-scarum, slaphappy.

devil-may-care (adjective)	happy-go-lucky (adjective)
cheerfully irresponsible	cheerfully irresponsible
marked by a carefree unconventionality or disreputableness