Sarcastic

Sarcasm is "a sharp, bitter, or cutting expression or remark; a bitter gibe or taunt". Sarcasm may employ ambivalence, although sarcasm is not necessarily ironic. "The distinctive quality of sarcasm is present in the spoken word and manifested chiefly by vocal inflection." The sarcastic content of a statement will be dependent upon the context in which it appears.

The word comes from the Greek σαρκασμός (sarkasmós) which is taken from σαρκάζειν (sarkázein) 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:

Tom piper, an ironicall Sarcasmus, spoken in derision of these rude wits, whych ...

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.

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 ...

Distinguishing sarcasm from banter, and referring to the use of irony in sarcasm, Bousfield writes that sarcasm is:

The use of strategies which, on the surface appear to be appropriate to the situation, but are meant to be taken as meaning the opposite in terms of face management. That is, the utterance which appears, on the surface, to maintain or enhance the face of the recipient actually attacks and damages the face of the recipient. ... sarcasm is an insincere form of politeness which is used to offend one's interlocutor.

John Haiman writes: "There is an extremely close connection between sarcasm and irony, and literary theorists in particular often treat sarcasm as simply the crudest and least interesting form of irony." Also, he adds:

First, situations may be ironic, but only people can be sarcastic. Second, people may be unintentionally ironic, but sarcasm requires intention. What is essential to sarcasm is that it is overt irony intentionally used by the speaker as a form of verbal aggression.

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Wikipedia