I find irony is a commonly misunderstood term. According to the Bedford Glossary of Literary Terms, irony is “a contradiction or incongruity between appearance or expectation and reality.” The requirement for something to be ironic is a shared assumption that a statement, action, or structural feature should be or ought to have been different than what it was (so, rain on your wedding day is only ironic if everyone presumed it would be sunny; otherwise it’s just coincidence). But irony is always a rhetorical technique, which means it accesses a specific audience who knows things ought to have been different. For example, the audience of a play usually knows more than characters who only appear in certain scenes; they are “in the know” and get the ironic joke at other characters’ expense (the audience of a Shakespearian soliloquy can hear a character saying he’s about to lie, but the other characters can’t, because by convention they aren’t supposed to be able to hear the soliloquy). But it is just as present in “verbal irony,” in which a speaker says one thing but means another—provided there is someone present to note the discrepancy and therefore not be fooled. That’s the difference between “irony” and “a lie”: with irony, you want your meaning to be understood (by someone present, even if not the person you are directly speaking to).
Characteristic forms of irony include artful understatement (also known as “meiosis,” or, if phrased as a contranegative, “litotes” [such as, if someone asks you how you feel, and you’re just scraping by, and you say “I am not dead” to convey how bad things are]), and its opposite, artful exaggeration (also known as “hyperbole” [such as the answer “I have simply never felt as outstanding!!” to convey the same meaning as above]). Irony is different from both sarcasm and satire, though either may employ irony; sarcasm is the purposefully nasty attempt to injure or ridicule somebody verbally; satire is the attempt to depict people, things, or ideas as low or lacking in order to better them.
Often, irony is your best way to access the intended audience of a text, because it operates via a rhetorical contract of sorts. T.S. Eliot’s poem The Waste Land begins: “April is the cruelest month, breeding / Lilacs out of the dead land…” Apparently, the speaker wants us to sympathize with his assessment of April’s cruelty, though the charge of lilac-breeding should probably puzzle us. The irony in these two lines (that is, April is not normally regarded as the cruelest month) lets us know immediately we are probably not part of the audience that would nod in agreement—it turns out later that we would need to be or feel dead in order to agree, so that’s probably for the best. Wilfred Owen’s antiwar poem “Anthem for Doomed Youth” begins with the strident lines “What passing-bells for these who die as cattle? / Only the monstrous anger of the guns.” This is a different type of irony, “situational” irony, which the poem uses to blame the English reader for her or his expectation that soldiers such as Owen would love to fight in World War One, and that it was possible to be heroic, to courageously succeed in trench warfare (a protracted conflict of attrition in which is became near-impossible to distinguish yourself as a combatant). The fact that things were so egregiously different, that men die “as cattle” instead of with the fanfare they were promised, works to select the guilty home-front audience that the irony pinpoints.
In each case of using irony, be sure to identify what you think is ironic, who recognizes it as being so, and what it means that irony has been employed.