de ‧ coy /ˈdiːkɔɪ/ BrE AmE noun [countable]
[ Date: 1500-1600 ; Language: Dutch ; Origin: de cooi 'the cage' (= structure of bars for keeping animals in) ]
1 . someone or something that is used to trick someone into going somewhere or doing something, so that you can catch them, attack them etc:
Officer Langley acted as a decoy to catch the rapist.
2 . a model of a bird used to attract wild birds so that you can watch them or shoot them
—decoy /dɪˈkɔɪ/ verb [transitive]