Snooper
/ˈsnuːpə(ɹ)/
"Snooper" in a Sentence (2 examples)
Bradly was embarrassed, detected in the character of a snooper. But he had to come on, short of bolting back in his tracks.
Apps like WhatsApp currently prevent any snoopers from reading your messages using end-to-end encryption, jumbling it up in such a way that only the recipient can de-jumble it.