(derogatory, slang) Someone who attempts to use knowledge of the arcane and technical rules governing a situation in a manner contrary to their intent to gain advantage.
“My kid,” Hambro said, “filibustering against going to bed. A real sea lawyer, that kid.”
Ralph Ellison. The Invisible Man (1952)
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When I'm in Parlyment and riding in my coach, I don't want none of these sea-lawyers in the cabin a-coming home, unlooked for, like the devil at prayers.