Defensively

from WordNet (r) 3.0 (2006)

defensively
    adv 1: in an apologetic and defensive manner; "`I felt it better
           you should know,' said Sir Cedric defensively"
    2: in a defensive manner; "the general conviction that our side
       is in the right and acting defensively over what Russians
       call the German question and Americans the Berlin crisis"
       [ant: {offensively}]

from The Collaborative International Dictionary of English v.0.48

Defensively \De*fen"sive*ly\, adv.
   On the defensive.
   [1913 Webster]