unbuckle

[ uhn-buhk-uh l ]

/ ʌnˈbʌk əl /

to unfasten the buckle or buckles of.

to undo a buckle.

Origin of unbuckle

First recorded in 1350–1400, unbuckle is from the Middle English word unboclen. See un-², buckle

At the end of the exercise, I unbuckle the vest and dump it on the ground.

Why Defend Being Overweight? |David Frum |January 4, 2013 |DAILY BEAST
She was meek enough now when the guards came to unbuckle the straps and free her.

The Real America in Romance, Volume 6; |John R. Musick
Unbuckle your weapons or you are dead men; be quick about it.

Memoirs of a Veteran Who Served as a Private in the 60's in the War Between the States |Isaac Hermann
I am anxiously awaiting the result, and trying to get rid of the crick in my neck and to unbuckle the smile in the meantime.

Punch, Or The London Charivari, Vol. 146., January 21, 1914 |Various

He threw off his jacket and began to unbuckle his cartridge belt.

The Broncho Rider Boys with the Texas Rangers |Frank Fowler
Without taking the time to pull off his vaquero boots or unbuckle his heavy spurs, Jos Parades hurried to his master.

Stronghand |Gustave Aimard