What is Crumple ?
Crumple is (verb) 1. to crush or to screw something up into a ball I heard him crumple up the paper and throw it into the wastepaper basket. 2. to become full of lines or folds Her shirt was crumpled because she had been lying on the grass. The box was full of crumpled bits of paper.
source: Easier English, Student Dictionary Upper Intermediate Level