irony

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The use of words to express something different from and often opposite to their literal meaning.
• noun An expression or utterance marked by a deliberate contrast between apparent and intended meaning.
• noun Incongruity between what might be expected and what actually occurs.
• noun An occurrence, result, or circumstance notable for such incongruity.
• noun Dramatic irony.
• noun Socratic irony.

from The Century Dictionary.

• Consisting of or resembling iron; also, resembling any of the distinctive qualities of iron.
• noun Simulated ignorance in discussion: a method of exposing an antagonist's ignorance by pretending to desire information or instruction from him.
• noun Hence Covert sarcasm; such a use of agreeable or commendatory forms of expression as to convey a meaning opposite to that literally expressed; sarcastic laudation, compliment, or the like.

from the GNU version of the Collaborative International Dictionary of English.

• noun Dissimulation; ignorance feigned for the purpose of confounding or provoking an antagonist.
• noun A sort of humor, ridicule, or light sarcasm, which adopts a mode of speech the meaning of which is contrary to the literal sense of the words.
• adjective rare Made or consisting of iron; partaking of iron; iron; ; -- In this sense iron is the more common term.
• adjective Resembling iron in taste, hardness, or other physical property.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Of or pertaining to the metal iron.
• noun A statement that, when taken in context, may actually mean something different from, or the opposite of what is written literally; the use of words expressing something other than their literal intention, notably as a form of humor.
• noun Dramatic irony: a theatrical effect in which the meaning of a situation, or some incongruity in the plot, is understood by the audience, but not by the characters in the play.
• noun Ignorance feigned for the purpose of confounding or provoking an antagonist; Socratic irony.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a trope that involves incongruity between what is expected and what occurs
• noun incongruity between what might be expected and what actually occurs
• noun witty language used to convey insults or scorn