overturn in WordNet English dictionary

1. cancel officially
   "He revoked the ban on smoking"; "lift an embargo"; "vacate a death sentence"
   revoke  annul  lift  countermand  reverse  repeal  overturn  rescind  vacate 
   
2. cause to overturn from an upright or normal position
   "The cat knocked over the flower vase"; "the clumsy customer turned over the vase"; "he tumped over his beer"
   overturn  tip over  turn over  upset  knock over  bowl over  tump over 
   
3. cause the downfall of; of rulers
   "The Czar was overthrown"; "subvert the ruling class"
   overthrow  subvert  overturn  bring down 
   
4. rule against
   "The Republicans were overruled when the House voted on the bill"
   overrule  overturn  override  overthrow  reverse 
   
5. change radically
   "E-mail revolutionized communication in academe"
   revolutionize  revolutionise  overturn 
   
6. turn from an upright or normal position
   "The big vase overturned"; "The canoe tumped over"
   overturn  turn over  tip over  tump over 
   

1. the act of upsetting something
   "he was badly bruised by the upset of his sled at a high speed"
   upset  overturn  turnover 
   
2. an improbable and unexpected victory
   "the biggest upset since David beat Goliath"
   overturn  upset