"a person who has or claims to have a great deal of authority or influence:"For me the connotation is an old west medicine show with a wagon emblazoned "The Great Panjandrum"
Dictionary.com goes with "a self-important or pretentious official" which is probably closer to what I was picturing.
From the Fulham and Hammersmith Chronicle:
Debt-ridden Hammersmith and Fulham Council spent more than £7,000 of public money on a party for its retiring chief executive in what has been described as an 'astonishing' use of tax payers' cash.
More than 450 council staff attended the Town Hall event in honour of Geoff Alltimes, who last month left his job as one of the highest paid local authority executives in the country with a pay-off of more than £200,000 and an annual pension thought to be in excess of £100,000.
Conservative councillors and colleagues of Mr Alltimes insisted the public would 'understand' why the authority, which has overseen cuts to community services and buildings worth millions of pounds in what it describes as its 'relentless drive for savings', pushed the boat out to mark his 36-year council career.