What is the meaning of operative?

noun

• A person secretly employed in espionage for a government.
  • synonyms: secret agent, intelligence officer, intelligence agent
• Someone who can be employed as a detective to collect information.
  • synonyms: private detective, PI, private eye, private investigator, shamus, sherlock

adjective

• Being in force or having or exerting force.
  • usage: "operative regulations"; "the major tendencies operative in the American political system"
• Relating to or requiring or amenable to treatment by surgery especially as opposed to medicine.
  • usage: "a surgical appendix"; "a surgical procedure"; "operative dentistry"
  • synonyms: surgical
• Effective; producing a desired effect.
  • usage: "the operative word"
• Of e. G. A machine. ( performing or capable of performing)
  • usage: "in running (or working) order"; "a functional set of brakes"
  • synonyms: running, functional, working