bright as a button/new penny

bright as a button/new penny

Of quick intelligence. The expression links the sparkle of a good mind with the shininess of a brass button or new coin. The adjective bright has been used in the sense of “quick-witted” and “intelligent” since about 1700.
See also: bright, button, new, penny
The Dictionary of Clichés by Christine Ammer
See also:
  • appropriate for
  • bulletproof
  • (as) quick as greased lightning
  • (as) slick as a whistle
  • man to man
  • man-to-man
  • muck-raking
  • back to back
  • back-to-back
  • no-brow