Oidor (en. Listener)
/oi̯ˈðoɾ/
Slang Meanings
Person who is always eavesdropping on others' conversations
That listener is in on all the conversations; he finds out everything.
Ese oidor está en todas las conversaciones, se entera de todo.
Someone who wants to know private information
Don't tell him your things; he's a natural listener.
No le cuentes tus cosas, es un oidor nato.