She re-purposed an old pair of jeans into a stylish backpack.

re-purposed 是动词 re-purpose 的过去式形式。re-purpose 由前缀 re-（表示"重新"）和动词 purpose（"用作...用途"）组成，字面意思是"重新赋予用途"，即"改造、重新利用"的意思。