noun (n)

• a faulty shot in billiards; the cue tip slips off the cue ball(noun.act)

  source: wordnet30
• a minor inadvertent mistake usually observed in speech or writing or in small accidents or memory lapses etc.(noun.act)

  Synonym:
  parapraxis, slip, slip-up
  

  source: wordnet30
• A false stroke with a billiard cue, the cue slipping from the ball struck without impelling it as desired.(noun)

  source: webster1913