What is the meaning of Buckling?

The act of fastening a buckle.

A folding into hills and valleys.

The action of giving in (slightly) to pressure or stress by developing a bulge, bending or kinking (with the eventual risk of collapsing).

Wavy; curly, as hair.

present participle and gerund of buckle

A young male domestic goat of between one and two years.

Smoked herring.

Source: wiktionary.org