A malapropism is the incorrect use of a word, often in an idiomatic expression, whereby the incorrect word sounds very similar to the intended, correct word. For example, in Shakespeare's Much Ado About Nothing, Dogberry exclaims, "Our watch, sir, have indeed comprehended two auspicious persons." The word "comprehended" is here used incorrectly in place of the word "apprehended," and the word "auspicious" is here used incorrectly in place of the word "suspicious." This is a good example of a malapropism, because the incorrect words also give to the utterance a completely different meaning to the one intended. Dogberry, ironically, comprehends very little, and the people he has apprehended are certainly not auspicious.
In act one, scene two of A Midsummer Night's Dream, Bottom uses a malapropism when he says, "I will aggravate my voice so that I will roar you as gently as any sucking dove." Here, Bottom is warning his fellow players, or actors, not to upset the ladies who will be watching their play. Bottom suggests that, to avoid upsetting the ladies, the players should play down the violence in some of the scenes.
He means to say that, should he play the part of the lion, he will do his part by mitigating or moderating his roar, so as not to frighten the ladies. Instead of the word "mitigate" or "moderate," however, Bottom mistakenly uses the word "aggravate." This malapropism is comical because it is the incorrect word and also because it implies the opposite of what the correct word means. To "aggravate" the lion's roar implies that Bottom will roar more loudly and more ferociously.
In act five, scene one, Bottom uses another malapropism when, playing the part of Pyramus, he says, "O wherefore, Nature, didst thou lions frame, / Since lion vile hath here deflower'd my dear." Bottom here uses the word "deflower'd," when he means "devoured." The image of a lion deflowering, or taking the virginity of his "dear," is, in the context of the play, ridiculous and grotesquely comic.