Sentence:  A <WSD>cut-out</WSD>, or intermediary, forms the link between two agents or between an agent and the outside world. He may know very little about the organization and just carry messages, or he may be a liaison officer who is able to answer questions and take decisions; but the important thing is that he should not undertake any other subversive activity. ... A <WSD>cut-out</WSD> should be able to contact inconspicuously each of the two agents between whom he is the link. 
Meaning of the word marked with <WSD> tags:  A trusted middleman or intermediary, especially in espionage.