A person who secretly investigates or pries into other people's affairs.

Someone who eavesdrops or spies, often for illicit purposes.

कान लगाकर सुनने वाला

English Usage: She felt uncomfortable knowing there was a snooper listening to her conversation.

Hindi Usage: उसे यह जानकर असहज महसूस हुआ कि एक कान लगाकर सुनने वाला उसकी बातचीत सुन रहा था।