In operation; that operates. / Involved in an operation.

present participle and gerund of operate

(mathematics, logic) An operation on logical values that changes true to false, and false to true.

The extent to which a system or device is operable.

In an operative manner.

plural of operativeness

(uncountable) The state or quality of being operative. / (countable) The result or product of being operative.

(Internet) A network operator on IRC.

plural of oper

The act of operating or working; operation.