operative

名词 operative:

1. a person secretly employed in espionage for a government
   同义词：secret agent, intelligence officer, intelligence agent
2. someone who can be employed as a detective to collect information
   同义词：private detective, PI, private eye, private investigator, shamus, sherlock

形容词 operative:

1. being in force or having or exerting force
2. of or relating to a surgical operation
3. relating to or requiring or amenable to treatment by surgery especially as opposed to medicine
   同义词：surgical
4. effective; producing a desired effect
   同义词：key
5. (of e.g. a machine) performing or capable of performing
   同义词：running, functional, working

1. This law becomes operative on 12 May.
   此法令自5月12日起生效。
2. The boss is hopping mad about it and `mad' is the operative word.
   老板对此事暴跳如雷--｀暴跳如雷＇这个成语在句中最重要。
3. The oil rig is now fully operative.
   石油钻塔现全面开工。
4. The station will be operative again in January.
   该车站将於一月份恢复使用。

op.er.a.tive

adj.（形容词）
Being in effect; having force; operating:
有效的；有力量的；行动的：
例句：
.Two major tendencies are operative in the American political system.(Heinz Eulau)
.在美国的政治体系中以两种主要潮流为主.(海因茨·奥劳)

Functioning effectively; efficient.
有效运用的，有效率的
Engaged in or concerned with physical or mechanical activity.
与体能有关的，或机械活动有关的
Of, relating to, or resulting from a surgical operation.
手术的：外科手术的，与外科手术有关的，由外科手术引起的
n.（名词）
A skilled worker, especially in industry.
熟练工人：熟练工人，尤指工厂技工

A secret agent; a spy.
特务，间谍
A private detective.
私人侦探

【引伸】
op.eratively
adv.（副词）