Source : Webster's Revised Unabridged Dictionary (1913)

Sharp \Sharp\, adv.
   1. To a point or edge; piercingly; eagerly; sharply. --M.
      Arnold.

            The head [of a spear] full sharp yground. --Chaucer.

            You bite so sharp at reasons.         --Shak.

   2. Precisely; exactly; as, we shall start at ten o'clock
      sharp. [Colloq.]

   {Look sharp}, attend; be alert. [Colloq.]

Source : WordNet®

look sharp
     v : act or move at high speed; "We have to rush!"; "hurry--it's
         late!" [syn: {rush}, {hasten}, {hurry}, {festinate}]