It's very obvious that Sheridan wishes to highlight the importance of the theme of his play through the title he has chosen :"The School for Scandal."
The central theme of Sheridan's "School for Scandal" is the vice of scandal mongering and its ill effects and the futility of trying to rid society of this vice.
David Garrick (1717 -1779) the author of the "Prologue" to the play introduces the theme in the very first line of the "Prologue" itself:
A School for Scandal! tell me, I beseech you,
Needs there a school this modish art to teach you?
He straightaway asks his audience very sarcastically whether it is necessary to establish a "school" to teach them the fashionable "art" of speaking ill of others, thus highlighting the ubiquitousness of this social vice.
Garrick concludes by remarking on the futility of Sheridan's attempt at getting rid of this hydra headed monster:
Is our young bard so young, to think that he
Can stop the full spring-tide of calumny?
Knows he the world so little, and its trade?
Alas! the devil’s sooner raised than laid.
So strong, so swift, the monster there’s no gagging:
Cut Scandal’s head off, still the tongue is wagging.
In Act I Sc1 and a little later in Act II Sc 2 Sheridan demonstrates the impracticality of preventing people from gossiping and spreading rumors about others. Maria and Sir Peter Teazle who oppose this vice are completely overwhelmed by the others:
Mrs. Can. True, true, child: but there’s no stopping people’s tongues. I own I was hurt to hear it, as I indeed was to learn, from the same quarter, that your guardian, Sir Peter, and Lady Teazle have not agreed lately as well as could be wished.
Mar. ’Tis strangely impertinent for people to busy themselves so.
Mrs. Can. Very true, child; but what’s to be done? People will talk—there’s no preventing it. Why, it was but yesterday I was told that Miss Gadabout had eloped with Sir Filagree Flirt. But, Lord! there’s no minding what one hears; though, to be sure, I had this from very good authority.
Mar. Such reports are highly scandalous.
Mrs. Can. So they are, child—shameful, shameful! But the world is so censorious, no character escapes. [Act I sc 1].
Lady Teaz. But Sir Peter is such an enemy to scandal, I believe he would have it put down by parliament.
Sir Pet. ’Fore heaven, madam, if they were to consider the sporting with reputation of as much importance as poaching on manors, and pass an act for the preservation of fame, as well as game, I believe many would thank them for the bill.
Lady Sneer. O Lud! Sir Peter; would you deprive us of our privileges?
Sir Pet. Ay, madam; and then no person should be permitted to kill characters and run down reputations, but qualified old maids and disappointed widows.
Lady Sneer. Go, you monster! [Act II Sc.2].
The title of Sheridan's play is thematically oriented. It has a manifold significance--
1. The title is phonetically alliterative with the repetition of the 'sk' sound in its two operative expressions--'school' and 'scandal', thus a sparkling example of wit and attention-drawing quality.
2. Sheridan initially thought of writing two separate plays, one called The Slanderers and the other Peter Teazle. Then he compressed the two plots into one.
3. The title at once introduces to us the socialized practice of scandal which is the central theme of the play. Scandal is related to meanness, jealousy, ill-intent, hypocrisy and a host of other upper class vices. It is also related to the cuckoldry plot of the Teazles and the plot of false sentiment as in the Surface brothers.
4. The word 'School' is very significant in the title. It implies the social institutionalization of scandal as a phenomenon. Lady Sneerwell's house is indeed a 'school' where quite self-consciously scandal is preached and practiced. As the Prologue suggests, Sheridan is all set to fight this proliferating Hydra-like scandal in its own den like a modern-day Don Quixote.