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

     n 1: a manually operated device to correct the operation of an
          automatic device
     2: the act of nullifying; making null and void; counteracting
        or overriding the effect or force of something [syn: nullification]
     v 1: rule against; "The Republicans were overruled when the House
          voted on the bill" [syn: overrule, overturn, overthrow,
     2: prevail over; "health considerations override financial
     3: counteract the normal operation of (an automatic gear shift
        in a vehicle)
     4: ride too hard, as of a horse