Definition of "bigwig"

[…] more innocently, and no doubt profitably, than if he had dined at a big-wig's board or bemused himself with smoke and beer among his brethren of the pen.

1891, Grace L. Keith Johnston, The Halletts: A Country Town Chronicle, volume 3, page 34

Before her hay-day, she attended many derbys under her dad's celebrity where she'd hobnob with the bigwigs in Millionaire's Row.

2016 May 5, “Reality star Bethenny Frankel talks hats, hangovers and her Kentucky Derby party at Empire City Casino”, in New York Daily News