Definitions of bumping
(also: seat bumping) denying seats, usually on an airline, to passengers with tickets because the airline sold too many tickets which resulted in the flight being overbooked
With voluntary bumping, the airline asks for volunteers and they give you free air miles or even a free flight coupon in return for your seat.
where an employee whose job is discontinued is given another employee's job resulting in the second employee being dismissed
The Employment Tribunal decided that bumping could give rise to a redundancy payment.