insider
n. countablen. someone who belongs to a specific group or organization and has special knowledge about it. Because they are on the inside, they know secrets that the public does not.
n. a person within a group or organization who possesses specialized knowledge or access to private information. Often used in financial or political contexts to describe those with non-public influence.
An insider leaked the secret plans to the press.
According to a company insider, the CEO plans to resign before the end of the fiscal year.
The investigation focused on whether the suspect acted as an insider, utilizing confidential data to execute trades before the merger was officially announced to the public.
From inside + -er.
Commonly used in the compound 'insider trading' to describe the illegal practice of trading on the stock market using private information.