Mightn't
verb
verb ·2 syllables ·Rare ·Advanced level
Definitions
Verb
- 1 might not (negative auxiliary) UK, archaic
"Her driver was new to the country; he mightn't be prepared for the leaping of the yellow water down dry arroyos, swift as the pouncings of a cat, or the snake-like slidings of tons of loosened rock and clay from the steep potreros […]"
Example
More examples"It mightn't have been my youngest brother's fault, but it wasn't mine either."
Etymology
From might + n't.
More for "mightn't"
Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.