backstop

noun

1. An object or a person put in the rear or in the back of something to reinforce, hold, support.
2. A default arrangement that holds if all else fails.

   “Irish prime minister Leo Varadkar, this morning, said a time-limited backstop would be unacceptable, and has previously promised to vote down the UK’s Brexit withdrawal deal unless it features a satisfactory backstop.”

   “"The 2½ years since have been about hammering home these points in any European capital that would listen. And in spite of capacity-sapping talks on the first point – Brexit, border and backstop – the Department of Foreign Affairs and other government departments have been working quietly to make good on the second.”

3. A wall or fence behind home plate.
4. (slang)A catcher; the position of catcher.

   “Bench may be the greatest catcher subjectively, but he's not statistically. Statwise, Yogi Berra is the all-time backstop, regardless of which measure you prefer. Berra's Total-Z is one-third of a standard deviation higher than Bench's, and his Core-Z average is a point better.”

5. The player who stands immediately behind the striking base.
6. (dated)The longstop.
7. (dated)The wicket-keeper.
8. Something serving to bolster or support a cover story etc.

   “[…] to be set up in Indonesia with a phony book and school supplies company established in New York City as a backstop.”

   “Closely representing an alibi, creating a backstop could involve such measures as having people available to verify the details of an agent's cover story.”

verb

1. (transitive)To serve as backstop for.
2. (transitive)To bolster, support.

   “Russia signalled on Monday it would backstop the European Union's bailout of Cyprus despite anger that the weekend rescue deal would impose heavy losses on uninsured depositors, many of them Russian.”

name

1. (UK)A proposed seamless border between Ireland and Northern Ireland in the event of Brexit.