From Longman Dictionary of Contemporary Englishconspiratorcon‧spi‧ra‧tor /kənˈspɪrətə $ -ər/ noun [countable] PLANsomeone who is involved in a secret plan to do something illegal
Examples from the Corpus
conspirator• She was not cut out to be a conspirator.• While singer Neneh Cherry moved on to crossover fame, her fellow conspirators took a back seat.• No, he had been set up by his fellow conspirators.• Thus the military conspirators could count on a growing area of civilian support.• It also shows that Brutus was quite naive towards the reasons which the other conspirators had for killing Caesar.• But how I would have preferred disaster to my role as rejected conspirator and failed renegade.• But then, in his very next speech he insists on shaking the hands of all of the conspirators. 