eavesdropping
verb
Definitions
To hear a conversation one is not intended to hear; to listen in.
Example: I hope nobody was eavesdropping on our conversation last night, since it got so personal.
To listen for another organism's calls, so as to exploit them.
noun
Definitions
Listening secretly to private conversation of others.
The interception of electronic communication.
The act of one organism listening for another's calls, so as to exploit them.