letch
/lɛtʃ/Definitions
1. noun
a person who is excessively or voyeuristically interested in other people’s sex lives or private affairs
“He was accused of being a bit of a gossip and a letch at the office.”
2. verb
to look at someone or something in a way that is considered rude or voyeuristic
“The men were caught letting her change in the locker room.”