WordWeb Online

1. Fall apart
   "the building crumpled after the explosion";
   - crumble, tumble, break down, collapse
    
2. Fold or collapse
   "His knees crumpled";
   - buckle
    
3. To gather something into small wrinkles or folds
   "She crumpled her lips";
   - pucker, rumple, cockle, knit
    
4. Become wrinkled, crumpled or creased
   "This fabric won't crumple";
   - rumple, wrinkle, crease, crinkle

Derived forms: crumpling, crumples, crumpled

Type of: break, cave in, change integrity, collapse, crease, crinkle, crisp, fall in, fold, fold up, founder, give, give way, ruckle, scrunch, scrunch up, wrinkle