fortify

Verb

• add alcohol to (beverages)
  • the punch is spiked!
    

• add nutrients to
  • fortified milk
    

• 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
    

• enclose by or as if by a fortification

• make strong or stronger
  • This exercise will strengthen your upper body
    
  • strengthen the relations between the two countries
    

Related words

• Synonyms: 
  spike , lace , arm , build up , gird , fort , strengthen , beef up
• Antonyms: 
  disarm , demilitarize , demilitarise , weaken