The term "peeping tom" is often associated with someone who spies on others in a manner that is considered intrusive or unethical. There are several synonyms for this term, including voyeur, stalker, and prowler. A voyeur is someone who enjoys observing others in private moments, often without their knowledge or consent. A stalker is someone who follows or watches someone persistently and obsessively, often with the intention of causing harm. Finally, a prowler is someone who sneaks around and observes others, often with the intention of committing a crime. These terms all describe behaviors that are considered inappropriate and invasive of others' privacy.