downer
n.something that makes you feel sad or ruins a good mood. It can also be a drug that makes you feel very relaxed or sleepy. If you tell a sad story at a party, people might call you a downer.
n.an event, person, or situation that has a depressing effect; also refers to a depressant drug. Informal in register; often used to describe someone who dampens the collective mood of a group.
“The news about the rain was a real downer.”
“I hate to be a downer, but we need to discuss the budget cuts before the meeting ends.”
“While the first half of the film was a vibrant comedy, the sudden shift into tragedy in the final act was a significant downer for the audience.”
Often used in the phrase 'a real downer' or 'to be a downer'.
From down + -er.
Perhaps related to tanner (“sixpence”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.