If you borrow something in a dream is usually a sign of loss - financial loss or poor support from friends. If you borrow money from someone, this means that you are going to lose large sums of money and you may also suffer from unshared love in a relationship. If you borrow a book from someone this forewarns of a future disappointment in a love affair.
On the other hand, if someone else borrows from you is a good omen which means that you are going to benefit from full support of friends or family whenever in need, including financial support.