practical joke
 惡作劇
 Joke, n.
 1. Something said for the sake of exciting a laugh; something witty or sportive (commonly indicating more of hilarity or humor than jest); a jest; a witticism; as, to crack good-natured jokes.
    And gentle dullness ever loves a joke.   --Pope.
 Or witty joke our airy senses moves
 To pleasant laughter.   --Gay.
 2. Something not said seriously, or not actually meant; something done in sport.
    Inclose whole downs in walls, 't is all a joke.   --Pope.
 In joke, in jest; sportively; not meant seriously.
 Practical joke. See under Practical.
 Prac·ti·cal a.
 1. Of or pertaining to practice or action.
 2. Capable of being turned to use or account; useful, in distinction from ideal or theoretical; as, practical chemistry. “Man's practical understanding.” --South. “For all practical purposes.” --Macaulay.
 3. Evincing practice or skill; capable of applying knowledge to some useful end; as, a practical man; a practical mind.
 4. Derived from practice; as, practical skill.
 Practical joke, a joke put in practice; a joke the fun of which consists in something done, in distinction from something said; esp., a trick played upon a person.
 ◄ ►
 practical joke
      n : a prank or trick played on a person (especially one intended
          to make the victim appear foolish)