operative Definition

operative
adj

1. Working; in action; having an effect.

Thesaurus: effective, efficient, influential, functional.
2. Said of a word: especially important or significant.

Example: ‘Must' is the operative word
Thesaurus: key, relevant, important, significant.
3. Relating to a surgical operation.

noun

1. A worker, especially one with special skills.

Thesaurus: employee, worker, artisan, operator.
(N Amer, especially US)
2. A private detective.

Derivative: operatively
adj

Derivative: operativeness
noun