1. [ adjective ] cheerfully irresponsible
Synonyms: devil-may-care freewheeling happy-go-lucky slaphappy carefree

"carefree with his money" "freewheeling urban youths" "had a harum-scarum youth"

Related terms: irresponsible
2. [ adverb ] in a wild or reckless manner
Synonyms: pell-mell

"dashing harum-scarum all over the place" "running pell-mell up the stairs"

3. [ noun ] a reckless impetuous irresponsible person
Synonyms: swashbuckler madcap hothead lunatic daredevil
Related terms: adventurer tearaway