spy; special agent; covert operative
Refers to an intelligence officer or agent engaged in clandestine operations, often in a military or espionage context.
He infiltrated the enemy country as a covert operative.
スパイ is a more general and common term for a spy, while 特殊工作員 is a formal, often military or intelligence-specific term for a special agent or covert operative.
Compound of 特殊 (special) + 工作 (operations, maneuvering) + 員 (member, personnel). The term likely originated in military or intelligence contexts to denote personnel engaged in special operations.