Which term refers to humor that suggests the opposite of its literal meaning?

The term that refers to humor suggesting the opposite of its literal meaning is irony. Irony is a rhetorical device where the intended meaning contrasts with the literal meaning. Often, this involves a situation where what actually happens is different from what is expected or where someone says something but means the opposite, adding a layer of wit and profundity.

For instance, if someone steps out into a torrential rainstorm and says, "What lovely weather we're having," this statement illustrates irony because the literal words suggest a positive quality about the weather, while the actual situation is quite the opposite. This device is frequently used in humor to enhance the effect of the statement and engage the audience by drawing attention to the discrepancy between appearance and reality.

The other terms do not fit this definition: metaphor refers to a figure of speech that makes a comparison between two unlike things without using "like" or "as"; personification gives human traits to non-human entities; and onomatopoeia refers to words that imitate sounds. None of these convey the same sense of contradiction inherent in irony.