The practical joke played on Malvolio raises themes which, by now, are familiar: the instability of identity, the importance of clothing in establishing one’s identity and position, and the illusions and delusions that we let ourselves fall into in the name of love. Like everyone else, from Orsino to Viola, Malvolio falls victim to the allure of romance. Despite his outward puritanism, he is as much a romantic as anyone—although his fantasy of marrying Olivia has as much to do with class-related ambition as it does with infatuation.
Malvolio’s desire to rise above his class spurs his self-delusion, but it also explains why Sir Toby and the others find his fantasy so ludicrous. Malvolio is an unsuitable match for Olivia not only because of his unattractive personality but also because he is not of noble blood. He is a commoner, while Olivia is a gentlewoman. As such, that Malvolio would imagine Olivia marrying him seems obscene to them. We may recall how interested Olivia is earlier to find out from young Cesario, on whom she has a crush, that he is a “gentleman”—meaning that he is of noble birth (I.v.249). In the class system of Shakespeare’s time, it would have seemed very strange for a noblewoman to marry below her rank.
Significantly, Malvolio’s fantasy of becoming Olivia’s husband involves changing his clothing: he imagines himself “in my branched velvet gown”—the garb of a wealthy noblemen, not of a steward (II.v.42–43). The letter also asks him to alter his clothing at the same time that he changes his personality. Just as the cross-dressing habits of Viola, the play’s central character, suggest a link between clothes and gender roles, so Malvolio’s ideas about what he will wear as an aristocrat suggest a connection between wardrobes and social hierarchies. Outward appearances, it seems, can shape reality—or so Malvolio imagines. Of course, just as Viola remains a woman beneath her clothes, Malvolio’s fantasies of velvet gowns and yellow stockings will do nothing to change his place in society.
Maria’s riddle, in which she plays with the letters of Malvolio’s name, is meant to be both obvious and ambiguous. Clearly, Malvolio is supposed to decide that it refers to him, but it also allows us to watch him wrench the evidence around to arrive at the conclusion at which he so desperately wants to arrive. Various critics have wondered whether there is any further meaning in the letters M.O.A.I., other than their obvious status as letters pulled out of Malvolio’s name, but no widely accepted answers have been put forward.
Malvolio’s comments upon recognizing what seems to be Olivia’s handwriting, however, do contain an obscene pun—about which Malvolio is evidently not supposed to be aware. Examining her handwriting, he notes, “[T]hese be her very c’s, her u’s, and her t’s, and thus makes she her great P’s” (II.v.78–79). C-U-T, or “cut,” was a Renaissance slang term for the vagina, and “thus makes she her great P’s” strongly suggests a reference to penises.