Definition of drum-beater in US English:

drum-beater

noun

  • 1A person who beats a drum.

  • 2Figurative (originally) a proponent of going to war; (more generally) a vehement supporter of a cause, idea, product, etc.

  • 3An implement used to beat a drum, especially a stick with a padded end.

Origin

Early 18th century; earliest use found in Athenian Oracle.