Source : WordNet®

pain in the ass
     n : something or someone that causes trouble; a source of
         unhappiness; "washing dishes was a nuisance before we got
         a dish washer"; "a bit of a bother"; "he's not a friend,
         he's an infliction" [syn: {annoyance}, {bother}, {botheration},
          {pain}, {infliction}, {pain in the neck}]