<p><strong>Noun</strong></p><ul><li>a person engaged, employed, or skilled in some branch of work, especially productive or industrial work; worker.</li><li>a detective.</li><li>a secret agent; spy.</li></ul><p><strong>Adjective</strong></p><ul><li>operating, or exerting force, power, or influence.</li><li>having force; being in effect or operation: laws operative in this city.</li><li>effective or efficacious.</li><li>engaged in, concerned with, or pertaining to work or productive activity.</li><li>significant; key: The operative word in that sentence is “sometimes.”</li><li>concerned with, involving, or pertaining to surgical operations.</li></ul><p><strong>Synonyms</strong></p><ul><li>workman</li><li>investigator</li><li>agent</li><li>serviceable</li><li>effectual</li></ul>