Definition of "operative"

operative

/ˈɒpəɹətɪv/

adjective
comparative more operative, superlative most operative
1. Effectual or important.
2. Functional, in working order.
3. Having the power of acting; hence, exerting force, physical or moral; active in the production of effects.
  Quotations
  It holds in all operative principles.
  1692–1717, Robert South, Twelve Sermons Preached upon Several Occasions, 6th edition, volumes (please specify |volume=I to VI), London: […] J[ames] Bettenham, for Jonah Bowyer, […], published 1727
  This call is operative not merely on the level of abstract theory.
  1988 April 2, Phillip Brian Harper, “Lesbians and gay men of color, speak out!”, in Gay Community News, page 9
4. Producing the appropriate or designed effect; efficacious.
5. Based upon, or consisting of, a surgical operation or operations.
noun
plural operatives
1. An employee or other worker with some particular function or skill.
2. A spy, secret agent, or detective.
3. A participant in an operation.