insider

noun

1. A person who has special knowledge about the inner workings of a group, organization, or institution.

   “Near-synonyms: initiate, old hand, habitué”

   “Heavy losses were sustained in Simms Petroleum, which took a greater toll from supposed "Wall Street insiders" than from the general public.”

   “He is also an astute ANC insider who spent ten years on Robben Island alongside Nelson Mandela and the other “grandees” of the movement.”

   “In a thread called “Calm Before the Storm”, and in subsequent posts, Q established his legend as a government insider with top security clearance who knew the truth about a secret struggle for power involving Donald Trump, the “deep state”, Robert Mueller, the Clintons, pedophile rings, and other stuff.”

   “That, as one of my more sceptical industry insiders put it, is because there is a reluctance to commit funds to any of these plans - and we can put the blame firmly on the fact that HS2 is eating up £7bn per year for the whole term of this parliament.”

2. A person who is within an enclosed space.

   “To the insider, the ceiling is like a small firmament twinkling with astral radiations.”