A rhetorical device from the Ancient Greek eirōneía meaning dissimulation or feigned ignorance. It is a technique or situation in which there is a sharp incongruity or discordance that goes beyond the simple and evident intention of words or actions.
Several types of irony should be distinguished:
Socratic irony; pretending to be dumber than you actually are. When a person asks questions, pretending not to understand, to lure the interlocutor into a logical trap.
Comic irony; “Gentlemen don’t fight, this is the war-room!” Irony that can be called humorous by general standards.
Dramatic irony; When the audience or reader knows a fictional character is making a mistake, because the audience has more information than the character. “Dive, thoughts, down to my soul:—here Clarence comes.” (Shakespeare’s Richard III Act I Scene I)
Tragic irony; A type of dramatic irony. In tragic irony, a character’s actions lead to consequences that are both tragic, and contrary to the character’s desire and intentions.
Situational irony; For instance: a vegetarian pacifist murdered in an abattoir.
Historical irony; A kind of situational irony that takes a long period of years for the irony to become evident.
Verbal irony; A sort of wordplay slightly less contradictory than sarcasm “As clear as mud.”
Verbal and situational irony are often used for emphasis in the assertion of a truth. The ironic form of simile, used in sarcasm, and some forms of litotes emphasize one’s meaning by the deliberate use of language which states the opposite of the truth — or drastically and obviously understates a factual connection.
In dramatic irony, the author causes a character to speak or act erroneously, out of ignorance of some portion of the truth of which the audience is aware. In other words, the audience knows the character is making a mistake, even as the character is making it. This technique highlights the importance of truth by portraying a person who is strikingly unaware of it.
In certain kinds of situational or historical irony, a factual truth is highlighted by some person’s complete ignorance of it or his belief in the opposite of it. However, this state of affairs does not occur by human design. In some religious contexts, such situations have been seen as the deliberate work of Divine Providence to emphasize truths and to taunt humans for not being aware of them when they could easily have been enlightened. Such ironies are often more evident, or more striking, when viewed retrospectively in the light of later developments which make the truth of past situations obvious to all.