n.1 a person or thing that discourages, or tempers enthusiasm.
2 a device that reduces shock or noise.
3 a metal plate in a flue to control the draught, and so the rate of combustion.
4 Mus. a pad silencing a piano string except when removed by means of a pedal or by the note's being struck.
5 esp. Austral. & NZ unleavened bread or cake of flour and water baked in wood ashes.
Phrases and idioms:
put a damper on take the vigour or enjoyment out of.