Is it permissible for a man to use women's perfume or oud oil, and is it permissible for women to use men's perfume?

It is permissible for a member of one gender to use perfume intended for the other, unless doing so constitutes imitation, in which case the perfume is predominantly associated with the other gender. It is then prohibited due to the impermissibility of imitation. Furthermore, using perfume intended for the other gender exposes its user to gossip and rumors, and a Muslim is responsible for safeguarding their honor. The Prophet, peace and blessings be upon him, demonstrated his concern for the reputation of his companions and taught his nation the way to avoid accusations. Therefore, a Muslim should not be lenient in such matters, even if they are known for their piety and devoutness.