General meaning:
* Operation: This is the most common noun form, referring to the act of working, functioning, or being in effect.
* Example: "The hospital's operation is running smoothly."
Specific meaning:
* Operation: This can also refer to a specific task or procedure, especially in a medical or surgical context.
* Example: "The surgeon performed a delicate operation."
* Operator: This refers to a person who operates a machine or system.
* Example: "The phone operator answered my call."
* Operative: This can refer to someone who works secretly, especially in a spy or intelligence agency.
* Example: "The operatives were sent on a mission to gather information."
The best choice will depend on the context and the specific meaning you want to express.