infiltrator

noun

1. One who infiltrates an organization or territory; an undercover or covert agent.

   “Sometimes Israelis were attacked by Arab infiltrators, and hardly a month went by without a West Jerusalemite either being killed or wounded.”

   “Suddenly, one of the cadre appeared from out of the darkness. "Hello, soldier", he said. "Do you have a light?” “Sure,” Jack replied, digging into his pocket for a book of matches. “Soldier! You are dead!” exclaimed the cadre. Jack had failed to challenge the infiltrator. The password was “Bronx”, the counter password was “Bombers”.”

   “Sudan’s President Omar al-Bashir blamed infiltrators for the recent deaths of anti-government protesters a speech Sunday while vowing to respect the will of the people in the 2020 elections.”

   ““We will remove every single infiltrator from the country, except Buddha, Hindus and Sikhs,” Bharatiya Janata Party (BJP) president Amit Shah told supporters in West Bengal on Thursday.”