Crumpling up a piece of paper is a common gesture of frustration or apathy. But, when it comes to describing this action, there are plenty of synonyms to choose from. You could say the paper was wrinkled, creased, folded, twisted, bent or crushed. Each of these words presents a slightly different image in the reader's mind. They could also lend themselves to various connotations. For instance, wrinkling or creasing could suggest carelessness, while folding or twisting might imply intentionality. No matter the nuance, the many synonyms for "crumpled up" offer a range of options for writers looking to color their language.