Wiki's definition of satire:

"Satire is often strictly defined as a literary genre or form; although in practice it is also found in the graphic and performing arts. In satire, human or individual vices, follies, abuses, or shortcomings are held up to censure by means of ridicule, derision, burlesque, irony, or other methods, ideally with the intent to bring about improvement. Although satire is usually meant to be funny, the purpose of satire is not primarily humour in itself so much as an attack on something of which the author strongly disapproves, using the weapon of wit.

A very common, almost defining feature of satire is its strong vein of irony or sarcasm, but parody, burlesque, exaggeration, juxtaposition, comparison, analogy, and double entendre are all frequently used in satirical speech and writing. The essential point, however, is that "in satire, irony is militant".[2] This "militant irony" (or sarcasm) often professes to approve (or at least accept as natural) the very things the satirist actually wishes to attack."