[1] : The Collaborative International Dictionary of English v.0.48

kill-joy \kill"-joy`\, n.
   one who causes gloom or grief; a dispiriting person; a
   spoilsport. --w. black.
   1913 webster

[2] : WordNet (r) 2.0

killjoy
     n : someone who spoils the pleasure of others syn: spoilsport,
          wet blanket, party pooper
see also:
spoilsport wet blanket party pooper 

[3] : Moby Thesaurus II by Grady Ward, 1.0

24 moby thesaurus words for "killjoy":
   cassandra, eeyore, calamity howler, crepehanger, cynic, damp,
   dampener, damper, defeatist, gloomy gus, grouch, grump, malcontent,
   malist, negativist, nihilist, pessimist, prophet of doom,
   retreatist, seek-sorrow, sourpuss, spoilsport, wet blanket,
   worrywart

Killjoy >> K Words
Killjoy, definition of term: Killjoy
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