decoy
n.a person or object used to trick someone into looking away from what is really happening. You use it to lead someone into a trap or away from a target.
n.a person or object used to lure an individual or entity into a trap or to distract attention from a primary target. Often used in military, hunting, or security contexts to misdirect an opponent.
“The police used a decoy car to catch the thieves.”
“Hunters often place wooden ducks on the water as a decoy to attract real birds to the area.”
“The fighter jets deployed flares as a decoy to confuse the heat-seeking missiles and allow the pilots to escape the combat zone safely.”
Often used with the verb 'to use' or 'to act as'.
From Dutch de + kooi, literally "the cage". Possibly related to verb coy (which itself may have been influenced by decoy).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.