dead giveaway

Of course, the loud buzzing of such drones and towels being blown away would have been a dead giveaway to the pool girls.

As with phone bills, major expenses or bills for jewelry and other gifts are a dead giveaway.

It was a dead giveaway when Young struck both cartels simultaneously, if Hunter had read the data correctly.

The red sweater with the terrycloth border and the white pants with a shortened left leg were a dead giveaway.

Despite the tight beam, any communication could be a dead giveaway.

The accidental use of a first name could mean a dead giveaway at the wrong time.

He drew near the rocket, thinking that the open hatch would be a dead giveaway.