What does the word ''Bunbury'' represent in The Importance of Being Earnest?

"Bunbury," or
"Bunburyism," refers to the imaginary friend of Algernon called Bunbury that he uses
to enable him to get out of awkward social engagements and to lead a double life. Bunbury finds
his parallel in Ernest, Jack's equally imaginary brother, whose wayward exploits allows Jack to
live both a respectable life of being an older, more responsible brother, but also he is able to
be more reckless and live as he wants to in town. Bunburyism refers therefore to the double life
that is such an important theme of the play, pointing towards the hypocrisy at the centre of
Victorian society. Both Ernest and Bunbury give Jack and Algernon respectively the appearance of
being much more virtuous and noble characters than they actually are. Note what Algernon says to
Jack when Jack tells him that when he marries Gwendolen he will be able to kill off his
brother:

Nothing will induce me to part with Bunbury, and
if you ever get married, which seems to me extremely problematic, you will be very glad to know
Bunbury. A man who marries without knowing Bunbury has a very tedious time of it.

This is typical humour from Wilde: Algernon suggests that, far from
removing the need for a double life, marriage necessitates it, and that living in close
proximity to somebody as in marriage makes it vital to have a double life in order for the
marriage to work successfully. There is a rather dark humour to this announement of Algernon's,
as on the one hand it clearly is a very funny comment, but on the other hand it points towards
the widespread hypocrisy within Victorian society and highlights the reality behind
marriage.