Source : Webster's Revised Unabridged Dictionary (1913)

Scrawl \Scrawl\, v. t. [imp. & p. p. {Scrawled}; p. pr. & vb. n.
   {Scrawling}.] [Probably corrupted from scrabble.]
   To draw or mark awkwardly and irregularly; to write hastily
   and carelessly; to scratch; to scribble; as, to scrawl a
   letter.

         His name, scrawled by himself.           --Macaulay.

Source : WordNet®

scrawled
     adj : written hastily or carelessly; "his scrawled signature"