The Etymology of Decoy
Decoy is the Dutch definite article fused to its noun: de kooi means "the cage", from Latin cavea (cage, hollow, enclosure — the same root as cage itself, and as cave). In the seventeenth-century Netherlands, fowlers built elaborate decoy ponds — funnel-shaped channels of water lined with reed screens and ending in covered tunnels — and used trained tame ducks to swim out, attract wild flocks, and lure them into the cage at the end of the channel. The technique was wildly successful, and English landowners copied it from the 1620s onward. They borrowed the word along with the practice, but the Dutch article fused into the noun in transit, leaving English with decoy as if it were a single root. The verb to decoy and the broader senses (a person used as a lure, a faked target, a misleading argument) all develop from the original duck-trap meaning across the seventeenth and eighteenth centuries.