RhymeZone: pushback definitions

Definitions of pushback:

noun: The act of repelling an enemy, etc.
noun: (aviation) A procedure in which an aircraft is pushed backwards away from the gate by some external force, usually a special tractor.
noun: Criticism of or resistance to a proposal, stance, or event.
noun: Summary expulsion of asylum seekers, especially when violating the principle of nonrefoulement.

(Definitions from Wiktionary)