WordNet sense 1 (an angular or rounded shape made by folding):

bend, crease, flexure, fold, plication

WordNet sense 2 (someone who tricks or coerces men into service as sailors or soldiers):

crimper

WordNet sense 3 (make ridges into by pinching together):

pinch

WordNet sense 4 (curl tightly):

crape, frizz, frizzle, kink, kink up