Latin
An outrage in the eyes of anyone with an affection for Plain English, Latinisms are (with flannel) the most obvious device by which the profession puts its language beyond the comprehension of the laiety. Some, in fairness, neatly capture concepts that their English equivalents make a bit of a meal of — like mutatis mutandis. Others are really just buzzwords that young lawyers learn to use to sound competent in front of their elders.
Latin buzzwords
Latin maxims
Then there are legal maxims — pithy aphorisms describing fundamental principles of the common law — which their authors inevitably render in Latin, thereby making them sound like they have existed since the dawn of curial civilization, rather than having just been made up on the spot to fudge an awkward precedent.
Of course, anyone can play that game: anyone, that is, lucky enough to know someone with O-Level Latin, who can therefore make up legal maxims to one’s heart’s content. This can be quite fun. Guess which ones are real and which ones aren’t: