Party pooper

• Defeat Johnson? Why? They say, he's a party pooper
• (informal) someone who spoils the pleasure of others
• Wet blanket

Wikipedia Word definitions in Wikipedia
Killjoy may refer to:

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also kill-joy , 1776, from kill (v.) + joy . Formerly used with other stems (such as kill-courtesy "boorish person," kill-cow "bully, big man," etc.).

WordNet Word definitions in WordNet
n. someone who spoils the pleasure of others [syn: spoilsport , wet blanket , party pooper ]

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM OTHER ENTRIES ▪ We wanted to do a sponsored dance after work but those killjoys in Head Office wouldn't let us.