crumple

v. estrujar, abuñolar, abuñuelar, ajar, arrugar, chafar, encoger, rabosear; ajarse, encogerse, estrujarse

arrugar

Ex: There is a tendency for smaller items to be pushed to the back of the drawer and possibly crumpled as the drawer is opened and closed = Lo normal es que las cosas más pequeñas se vayan desplazando hacia la parte trasera del cajón y que posiblemente se arrugen al abrir y cerrarlo.

(v.) = arrugar, abollar
Ex: There is a tendency for smaller items to be pushed to the back of the drawer and possibly crumpled as the drawer is opened and closed = Lo normal es que las cosas más pequeñas se vayan desplazando hacia la parte trasera del cajón y que posiblemente se arrugen al abrir y cerrarlo.