- 1 [transitive, intransitive] to fasten something or be fastened with a buckle buckle (something) She buckled her belt. buckle (something on/up) He buckled on his sword. These shoes buckle at the side.
- 2[intransitive, transitive] to become crushed or bent under a weight or force; to crush or bend something in this way The steel frames began to buckle under the strain. (figurative) A weaker man would have buckled under the pressure. buckle something The crash buckled the front of my car.
- 3[intransitive] when your knees or legs buckle or when you buckle at the knees, your knees become weak and you start to fall Phrasal Verbsbuckle down (to something)buckle up
NAmE//ˈbʌkl//Verb Forms present simple I / you / we / they buckle
he / she / it buckles
past simple buckled
-ing form buckling