an officer of a corporation or others who have access to private information about the corporation's operations
"The stock price plummeted after the insider accidentally mentioned a pending factory closure at dinner."
A person who has special knowledge about the inner workings of a group, organization, or institution.
"As an insider at the tech company, she knew about the new project before it was ever announced to the public."
In plain English: An insider is someone who has special knowledge about a group or company because they work there or are part of it.
"The insider shared some confidential details about the company's new product launch with a few trusted friends."
Usage: Use "insider" to describe someone with privileged access to private information or confidential details within a specific group or organization. This term applies whether the person holds an official position or simply possesses non-public knowledge through their connections.
The word insider is formed by combining the preposition inside with the suffix -er to denote someone who is within a group or organization. This straightforward construction directly describes a person located on the interior side of something.