If you refer to something or someone as a decoy, you mean that they are intended to attract people's attention and deceive them, for example, by leading them into a trap or away from a particular place.
双语例句
例： A plane was waiting at the airport with its engines running but this was just one of the decoys.
一架开动了引擎的飞机侯在机场，但这只是诸多诱饵中的一个。