Definition from Wiktionary, the free dictionary
capper (plural cappers)
- One that caps.
- A device or person that applies caps, as to bullets or bottles.
- A person that makes or sells caps.
- A finale.
2009, February 1, “Joe Queenan”, in Super Bowl Suits:
- The real capper is when St. John starts fawning over Hugh Hefner, host of the finest Super Bowl party known to man, musing: “The question isn’t whether Hef is the hippest octogenarian on the planet.
- (US, slang, dated) A by-bidder; a decoy for gamblers.
One that caps
A device or person that applies caps, as to bullets or bottles
A person that makes or sells caps