This word can have several meaning to
help defuse an argument or let some one know of your displeasure or delight. It is a word commonly shouted during a silence or in a public place to attract attention to yourself.
I can also be used when you are being told a story you are dis interested in to indicate you want the other person to shut up.
The word should be shouted loudly and in the voice of a upper class
gentleman from West
London.