Sarcasm
Sarcasm is the use of irony to mock or convey contempt.
"The distinctive quality of sarcasm is present in the spoken word and manifested chiefly by vocal inflections". The sarcastic content of a statement will be dependent upon the context in which it appears.
Origin of the term
The word comes from the Greek σαρκασμός (sarkasmos) which is taken from σαρκάζειν meaning "to tear flesh, bite the lip in rage, sneer".
It is first recorded in English in 1579, in an annotation to The Shepheardes Calender by Edmund Spenser:
However, the word sarcastic, meaning "Characterized by or involving sarcasm; given to the use of sarcasm; bitterly cutting or caustic", doesn't appear until 1695.
Usage
In its entry on irony, Dictionary.com describes sarcasm thus:
In sarcasm, ridicule or mockery is used harshly, often crudely and contemptuously, for destructive purposes. It may be used in an indirect manner, and have the form of irony, as in "What a fine musician you turned out to be!," "It's like you're a whole different person now...," and "Oh... Well then thanks for all the first aid over the years!" or it may be used in the form of a direct statement, "You couldn't play one piece correctly if you had two assistants." The distinctive quality of sarcasm is present in the spoken word and manifested chiefly by vocal inflection ...