"a fold in the napkin"
"a crease in his trousers"
"a plication on her blouse"
"a flexure of the colon"
"a bend of his elbow"
"his face has many lines"
"ironing gets rid of most wrinkles"
"The dress got wrinkled"
"crease the paper like this to make a crane"
"furrow one's brow"
"graze the skin"
"This fabric won't wrinkle"