Definition of rum-chaser in English:

rum-chaser

noun

US
  • 1Informal a person who habitually drinks rum; = rumhound (rare).

  • 2(During the Prohibition era) a law enforcement agent who pursues rum runners.

  • 3(During the Prohibition era) a coastguard speedboat used for pursuing rum-smugglers or their ships.

Origin

Early 20th century; earliest use found in The Boston Globe.