This paper is an attempt to answer the riddle set up by Malvolio's cryptic question which occurs in the box-tree scene (2.5) of Twelfth Night. The essay surveys a number of alternative solutions proposed by critics, editors, and actors. All are found, in their own ways, to be wanting: some are exposed as literal minded, too arcane, reliant upon language games that are unavailable to a theater audience or flawed by chronology. As the first step in decoding the puzzle, the paper rehearses a Renaissance view of semantics, according to which sense arises from utterances quintessentially — not, as modern linguistics would have it, approximately. Language, that is, is shown to signify inherently rather than conventionally. This linguistic veracity is shown to condemn Malvolio as he repeats an acrostic which he doesn't perceive, even while he utters it. The paper proposes that M.O.A.I. alludes to Sir John Harington's The Metamorphosis Of A Iax.