Heinlein said that ‘Civil Servant’ is exactly equal to ‘Civil Master’. Heinlein implied he filched this term from George Bernard Shaw, who probably got it from Shakespeare, who undoubtedly borrowed it from the Romans who stole everything from the Greek philosophers…
oxymoron: a figure of speech by which a locution produces an incongruous, seemingly self-contradictory effect, as in "cruel kindness" or "to make haste slowly."