You can use bathroom window privacy films for this purpose. These films come in varying designs, from frosted to patterned, and can either adhere to the glass or cling on statically. Options include the Coavas Adhesive Frothed Bathroom Window Film or the Privacy Window Film Removable Covering. These provide privacy while still letting in natural light. They're easy to install and remove, making them excellent for both long-term use and temporary situations.