ETYM French déception, Latin deceptio, from decipere, deceptum. Related to Deceive.
The act of deceiving; SYN. deceit, dissembling, dissimulation.
In warfare, the use of dummies, decoys, and electronics to trick the enemy into believing in and preparing to defend against armies that do not exist.
The Allied ground offensive in the 1991 Gulf War was launched 160 km/100 mi W of where the Iraqi army was led to believe it would take place. The deception techniques used completely wrong-footed the Iraqi forces.