Why is the ninth month called September?
1570s, sarcasmus, from Late Latin sarcasmus, from late Greek sarkasmos "a sneer, jest, taunt, mockery," from sarkazein "to speak bitterly, sneer," literally "to strip off the flesh," from sarx (genitive sarkos) "flesh," properly "piece of meat," from PIE root *twerk- "to cut" (cf. Avestan thwares "to cut"). Current form of the English word is from 1610s. For nuances of usage, see humor.
A form of irony in which apparent praise conceals another, scornful meaning. For example, a sarcastic remark directed at a person who consistently arrives fifteen minutes late for appointments might be, “Oh, you've arrived exactly on time!”