crumple

Concise Oxford English Dictionary © 2008 Oxford University Press:
crumple/ˈkrʌmpl/

▶verb

• 1 crush or become crushed so as to be creased and wrinkled.

• 2 suddenly lose force, effectiveness, or composure.

▶noun a crease or wrinkle.

– derivatives
crumply adjective.

– origin ME: from obs. crump ‘make or become curved’, from OE crump ‘bent, crooked’, of W. Gmc origin.