noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A reversal or undoing of tasks previously done (often in reverse order).
2. 2
   A reversed countdown (i.e. ascending numbers) in response to problems leading up to a launch.

Etymology

Deverbal from back out.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.