Buckle

Schnalle

(metal clasp with a hinged tongue or a spike)

biegen

(to cause (something) to bend, or to become distorted)

nachgeben

(of a person: to (suddenly) cease resisting pressure or stress — see also give in, give way, yield)

sich biegen

(of a thing: to collapse or distort under physical pressure)

zusammenbrechen

(of a person: to (suddenly) cease resisting pressure or stress — see also give in, give way, yield)