Other forms: dampers
When you put a damper on something, you restrain it or inhibit it. Putting a damper on things usually means bringing them down — your car troubles might put a damper on your travel plans.
A forecast of afternoon thunderstorms will put a damper on your picnic preparations, and being assigned a long research paper on Friday might be a damper on your weekend free time. More physical kinds of dampers include a device that restrains air in a chimney, by blocking or directing its flow, and a pad that's made to soften or muffle the sound from a musical instrument.