The engineer sent a countersignal to cancel out interference from the initial transmission.

Activists often countersignal by posting cheerful, apolitical photos to create a false impression about their organizing.

Despite the initial briefing, the team ignored the countersignals and proceeded with the operation.

The contract required a countersignature from the department head before it could take effect.

The board required two countersignatures on the contract before it could be executed.

The contract required two independent countersignatories before it could be enacted.

The contract required a countersignatory before it could be executed.

When the protest leaders declared their demands, the authorities countersignalled by announcing stricter regulations.

By deliberately countersignalling his indifference, he hinted that he was actually very invested in the outcome.