weaken


weaken (http://definr.com/weaken)

     v 1: lessen the strength of; "The fever weakened his body" [ant:
          strengthen]
     2: become weaker; "The prisoner's resistance weakened after
        seven days" [ant: strengthen]
     3: destroy property or hinder normal operations; "The
        Resistance sabotaged railroad operations during the war"
        [syn: sabotage, undermine, countermine, counteract,
         subvert]
     4: reduce the level or intensity of; "de-escalate a crisis"
        [syn: de-escalate, step down] [ant: escalate]
     5: lessen in force or effect; "soften a shock"; "break a fall"
        [syn: dampen, damp, soften, break]