noun 1.an act or instance of tapping telephone or telegraph wires for evidence or other information.
verb (used with object) 2.to obtain (information, evidence, etc.) by tapping telephone or telegraph wires: to wiretap conversations.
3.to listen in on by means of a wiretap: to wiretap a telephone; to wiretap a conversation.
verb (used without object) 4.to tap telephone or telegraph wires for evidence, information, etc.
adjective 5.pertaining to or obtained by wiretap.