Opposite words for defend:
take back, forsake, withdraw, cave, overrun, abandon, capitulate, assault, assail, storm, attack, abjure, refute, besiege, bombard, retract, controvert, recant, beset, yield, rebut, submit, disprove, reverse, prosecute, switch.
Usage samples:
  1. A man must defend himself."
    "An Egyptian Princess, Volume 9.", Georg Ebers.
  2. Defend us, there's blood on him!"
    "Princess Maritza", Percy Brebner.
  3. Take your rifle again, and help to defend the place.
    "Middy and Ensign", G. Manville Fenn.
  4. Nor was there absent from her a certain pride in that she had done the thing that was right, and had dared to defend herself.
    "Lady Anna", Anthony Trollope.