Incomplete Glossary for John le Carré's "Tinker, Tailor, Soldier, Spy"

I recently finished reading my first le Carré novel, The Spy Who Came In from the Cold. I really enjoyed the book and decided to read another le Carré spy novel, Tinker, Tailor, Soldier, Spy. While it was relatively easy to read The Spy Who without knowing specific spy jargon, Tinker, Tailor is proving much more difficult to read without knowing spy terms from the era. I thought it might help other readers if I shared my notes on words that confused me since a lot of them are not in any dictionary and took some digging to find the definitions.

This is not a complete glossary. Please drop a comment if there are errors or terms that I missed.

Burn: Blackmail.

Centre: KGB. Short for Moscow Centre.

Circus: MI6. Fictionally based in Cambridge Circus in the le Carré novels.

The Competition: MI5, internal counter-espionage. Roughly similar to the American FBI.

Funnies: Spies. Apparently Mendel uses that term because he is an outsider and not a member of the Circus himself.

Hood: An agent who engages in illegal activity.

Janitor: Circus headquarters staff.

Lamplighter: A surveillance agent or courier.

Legman: An assistant to a secret agent. Someone who plays a supporting role to an agent during a mission. Note: I couldn’t find a definition anywhere for this one so what I have here is a guess based on context.

Mother: Trusted typist or secretary at Circus headquarters.

Pavement artist: An agent who tracks or follows enemy spies. (An artist at walking the pavement/sidewalk)

Pink: Having Communist sympathies. (Not quite red, but not anti-communist either).

Resident: A spy stationed somewhat permanently in a foreign country.

Scalp-hunter: Secret agents that handle jobs too dirty or risky for agents in the field.