Question

What is the underlying meaning of: "Cleverness becomes a public nuisance."

Answer 1

In 'The importance of being earnest', a scintillating work by Oscar Wilde, there is a conversation between two characters (Jack Worthing and Algernon Moncreiff) wherein Jack says these words to the other, in the context of the work the meaning could possibly be a denunciation of the 'cleverness' people feel their lives to be imbibed with and dysfunctional without. It could even be a satirical take on what Wilde thought of the 'clever' people of his day. His wordplay, more often than not, is just that; a play.
In a literal context it could refer to the ever evolving (and expanding) ego sphere that people form around themselves masked in the form of cleverness, laying claim to fame and fortune based upon this cleverness while in effect only causing inconvenience to the public. Hence, a nuisance for those fed up of the clever and in search of fools, fools who (as Wilde says) are fools for talking about the clever.