[1] : WordNet (r) 2.0

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
see also:
annoyance bother botheration pain infliction pain in the neck 

Ass >> A Words
Ass, definition of term: Ass
ass_pag1.html