fortify in WordNet English dictionary

1. prepare oneself for a military confrontation
   "The U.S. is girding for a conflict in the Middle East"; "troops are building up on the Iraqi border"
   arm  build up  fortify  gird 
   
2. make strong or stronger
   "This exercise will strengthen your upper body"; "strengthen the relations between the two countries"
   strengthen  beef up  fortify 
   
3. enclose by or as if by a fortification
   fortify  fort 
   
4. add alcohol to (beverages)
   "the punch is spiked!"
   spike  lace  fortify 
   
5. add nutrients to
   "fortified milk"
   fortify