Satire is a genre of literature, and sometimes graphic and performing arts, in which vices, follies, abuses, and shortcomings are held up to ridicule, ideally with the intent of shaming individuals, corporations, government or society itself, into improvement. Although satire is usually meant to be humorous, its greater purpose is often constructive social criticism, using wit as a weapon and as a tool to draw attention to both particular and wider issues in society.
A feature of satire is strong irony or sarcasm—”in satire, irony is militant”—but parody, burlesque, exaggeration, juxtaposition, comparison, analogy, and double entendre are all frequently used in satirical speech and writing. This “militant” irony or sarcasm often professes to approve of (or at least accept as natural) the very things the satirist wishes to attack.
Satire is nowadays found in many artistic forms of expression, including literature, plays, commentary, television shows, and media such as lyrics.
Dallas Baptist University Excellent explanation of the characteristics of the various types of satire.
Encyclopedia.com Literary entry on satire.
Les Bizarrables Satirical song lyrics based on those from the musical Les Miserables.