inelastic

Inelastic describes something that doesn't stretch or spring back.

Literally, an inelastic material resists deformation: The cheap rubber band was inelastic and snapped.

In economics, inelastic demand or supply doesn't change much when prices shift—people buy roughly the same amount of gasoline regardless of cost because they need it.

An inelastic collision is one where objects don't bounce apart but stick together, losing kinetic energy.