Webster’s Revised Unabridged Dictionary · 1913 Flipper Flip′per (·pẽr), n. [Cf. Flip, Flippant.] 1. (Zoöl.) A broad flat limb used for swimming, as those of seals, sea turtles, whales, etc. 2. (Naut.) The hand. [Slang] ‹ Flippantness Flirt ›