KILLJOY

spoilsport, killjoy, wet blanket, party pooper

(noun) someone who spoils the pleasure of others

Source: WordNet® 3.1

Etymology

Noun

killjoy (plural killjoys)

A person who is anti-fun, or prevents others from having fun.

Synonyms

• buzzkill, miserabilist, dampener, party pooper, spoilsport; see also spoilsport

Source: Wiktionary

Kill"-joy`, n.

Definition: One who causes gloom or grief; a dispiriting person. W. Black.

Source: Webster’s Unabridged Dictionary 1913 Edition