Big wig

Wigs were expensive to purchase and to keep in condition and were the preserve of the powerful and wealthy. Ostentation was the order of the day in Bourbon France and over time the wigs became bigger, often to the point of absurdity and requiring of scaffolding.
It isn't difficult to imagine how the term 'big-wig' emerged to refer to the rich and powerful.
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These days the term is used to indicate someone important, although in my opinion someone who thinks they are important but it isn't legitimate. Someone like...