Source : Webster's Revised Unabridged Dictionary (1913)

Snappish \Snap"pish\, a.
   1. Apt to snap at persons or things; eager to bite; as, a
      snapping cur.

   2. Sharp in reply; apt to speak angrily or testily; easily
      provoked; tart; peevish.

            The taunting address of a snappish misanthrope.
                                                  --Jeffrey.
      -- {Snap"pish*ly}, adv. -- {Snap"pish*ness}, n.

Source : WordNet®

snappishly
     adv : in an ill-natured and snappish manner; "`Don't talk to me
           now,' she said snappishly"