unbear means to remove or loose the bearing rein of (a horse). Lexicurio rates it Sui generis — a strength score of 88 out of 100.
Etymology
From un- + bear.
verb
- To remove or loose the bearing rein of (a horse).“[…] he dashes to his destination at such a speed that when he stops the horse half smothers him in a cloud of steam.
"Unbear him half a moment to freshen him up, and I'll be back."”