There are multiple definitions - click on the translation that matches your context.

Abhören des Telefonverkehrs

Substantiv

full

wiretapping

noun

Comparative law notes

Austria

This is the correct phrase in US English.

Definitions of wiretapping

English

the act of connecting a device to a telephone line to monitor or listen to conversations secretly

General Michael Hayden ran the National Security Agency (NSA) in 2001 when Mr Bush approved the wiretapping.