ˌwet ˈblanket / $ ˈ. ˌ../ noun [countable]
informal someone who seems to want to spoil other people’s fun, for example by refusing to join them in something enjoyable that they are doing

[TahlilGaran] Dictionary of Contemporary English ▲

wet blanket
[informal]
someone who does or says something that stops other people from enjoying themselves.
I don't want to be a wet blanket, but you really must play your music more quietly or you'll disturb the people next door.

[TahlilGaran] English Idioms Dictionary ▲

wet blanket
person who discourages others from having fun
He is a wet blanket so we never invite him to our parties.

[TahlilGaran] English Idioms Dictionary ▲

wet blanket
n., informal A person or thing that keeps others from enjoying life.
The teenagers don't invite Bob to their parties because he is a wet blanket.
The weatherman throws a wet blanket on picnic plans when he forecasts rain.
Compare: CREPE HANGER.

[TahlilGaran] English Idioms Dictionary ▲