devil-may-care vs harum-scarum

devil-may-care is not a noun while harum-scarum is a noun.

Word	Noun	Adjective	Verb	Adverb
devil-may-care	No	Yes	No	No
harum-scarum	Yes	Yes	No	Yes

As adjectives, devil-may-care and harum-scarum are synonyms defined as:

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

devil-may-care (noun)	harum-scarum (noun)
	a reckless impetuous irresponsible person

devil-may-care (adjective)	harum-scarum (adjective)
cheerfully irresponsible	cheerfully irresponsible
marked by a carefree unconventionality or disreputableness

devil-may-care (adverb)	harum-scarum (adverb)
	in a wild or reckless manner