The Collaborative International Dictionary of English v.0.48:

Premunite \Prem`u*nite"\, v. t. [L. praemunitus, p. p. of
   praemunire to fortify in front; prae before + munire to
   fortify.]
   To fortify beforehand; to guard against objection. [Obs.]
   --Fotherby.
   [1913 Webster]