ass in WordNet English dictionary

1. the fleshy part of the human body that you sit on
   "he deserves a good kick in the butt"; "are you going to sit on your fanny and do nothing?"
   buttocks  nates  arse  butt  backside  bum  buns  can  fundament  hindquarters  hind end  keister  posterior  prat  rear  rear end  rump  stern  seat  tail  tail end  tooshie  tush  bottom  behind  derriere  fanny  ass 
   
2. slang for sexual intercourse
   fuck  fucking  screw  screwing  ass  nooky  nookie  piece of ass  piece of tail  roll in the hay  shag  shtup 
   
3. hardy and sure-footed animal smaller and with longer ears than the horse
   ass 
   
4. a pompous fool
   ass