spy on

US /spaɪ ɑːn/
UK /spaɪ ɑːn/
"spy on" picture
1.

to secretly watch someone or something, especially to obtain information

:
•
The government was accused of trying to spy on its own citizens.
•
She felt like someone was spying on her.
:
monitorobservewatchsurveileavesdrop
:
spy