Source : Webster's Revised Unabridged Dictionary (1913)

Harum-scarum \Har"um-scar"um\, a. [Cf. hare,v. t., and scare, v.
   t.]
   Wild; giddy; flighty; rash; thoughtless. [Colloq.]

         They had a quarrel with Sir Thomas Newcome's own son, a
         harum-scarum lad.                        --Thackeray.

Source : WordNet®

harum-scarum
     adj : cheerfully irresponsible; "carefree with his money";
           "freewheeling urban youths"; "had a harum-scarum youth"
           [syn: {carefree}, {devil-may-care}, {freewheeling}, {happy-go-lucky},
            {slaphappy}]
     n : a reckless impetuous irresponsible person [syn: {daredevil},
          {madcap}, {hothead}, {swashbuckler}, {lunatic}]
     adv : in a wild or reckless manner; "dashing harum-scarum all over
           the place"; "running pell-mell up the stairs" [syn: {pell-mell}]