G-Man (slang) G-Man (slang) G-Man (short for "Government Man") is an American slang term for special agents of the United States Government. It is specifically used as a term for a Federal Bureau of Investigation (FBI) agent. "G-Man" is also a term used for members of G Division, essentially a British anti-rebel police unit operating out of Dublin Castle prior to Irish Independence in 1922. Colonel Ned Broy uses the term in his official testimony for the Irish Army's Bureau of Military History in their archive of the Easter Rising (1916) and the Irish War of Independence (1919-1921). According to the "Merriam-Webster
G. Callen son. After Hetty takes over the interrogation, she allows him to escape to finish what he started. Callen and Sam go to his rescue and Callen discovers that his father had a child with a woman after he helped her move to the U.S. That child has since become a parent, so Callen has a half-sister and is now an uncle. In the episode "Payback", Callen learns from Hetty that Joelle is an undercover CIA agent who has been assigned by rogue agency moles to spy on him. Feeling betrayed, Callen permanently severs his ties with Joelle. G. Callen G.