The paper is about a chreia—a one-liner used as a grammatical exercise sentence—that presents Pythagoras as proscribing an expression from admissible linguistic usage. This injunction is funny, because it can be construed as Pythagoras railing against the use of a particular variant form of an adjective—and also as against the use of items denoted by that adjective. In the paper I add to this line of interpretation the further point that the chreia also claims that in this latter construal the injunction was Pythagoras’s signature insight, making him the philosopher that he was