spoilsport

American  

[spoil-spawrt, -spohrt] / ˈspɔɪlˌspɔrt, -ˌspoʊrt /

noun

1. a person whose selfish or unsportsmanlike attitudes or actions spoil the pleasure of others, as in a game or social gathering.

---

spoilsport British  

/ ˈspɔɪlˌspɔːt /

noun

1. informal a person who spoils the pleasure of other people by his actions or attitudes

---

Etymology

Origin of spoilsport

First recorded in 1815–25; from phrase spoil the sport

Example Sentences

And rains play a spoilsport here as well.

From BBC

For days, northern California newspapers kicked around fierce, spoilsport claims.

From Seattle Times

Never mind the spoilsport who defines college as “those magical seven years between high school and your first warehouse job.”

From Washington Post

ERB Inc. scrupulously guards the still-lucrative legacy of this outsized — only spoilsports would say outdated — out-and-out genius of popular genre fiction.

From Los Angeles Times

But rising interest rates and fears of a recession may play spoilsport in an industry where most vehicle purchases are financed with loans, analysts say.

From Reuters