3 Answers

i·ro·ny1
 
noun
1.
the expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect.
synonyms: sarcasm, causticity, cynicism, mockery, satire, sardonicism  
antonyms: sincerity
a state of affairs or an event that seems deliberately contrary to what one expects and is often amusing as a result.
plural noun: ironies
"the irony is that I thought he could help me"
synonyms: paradox, incongruity

If someone ran into the back of your car,  you could say, and it would be  considered "ironic":

"Well, I never liked this car anyway"   or, "Thank God! I was hoping to get the bumpers replaced"  or   "What! You hit the car and can't do enough damage to total it?"

 

Irony (from the Ancient Greek, meaning dissimulation or feigned ignorance), in its broadest sense, is a rhetorical device, literary technique, or event characterized by an incongruity, or contrast, between what the expectations of a situation are and what is really the case, with a third element, that defines that what is really the case is ironic because of the situation that led to it. The term may be further defined into several categories, among which are: verbal, dramatic, and situational.
Verbal, dramatic, 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 can emphasize one's meaning by the deliberate use of language which states the opposite of the truth, denies the contrary of the truth, or drastically and obviously understates a factual connection.
Other forms, as identified by Thirlwall, include dialectic and practical irony.

http://en.wikipedia.org/wiki/Irony

Hmmmm .... That's why I never use that word.  : )