I found out what a dickens is:
dickens - (what the dickens, in dickens' name, hurts like the dickens, etc) - Dickens is another word for devil, and came to be used as an oath in the same way as God, Hell, Holy Mary, etc. Brewer (dictionary of phrase and fable 1870) explains that the 'dickens' oath, is a perversion (variation) of, and derived from 'Nick' and 'Old Nick'. The dickens expression appeared first probably during the 1600's. The etymology of 'nick' can be traced back a lot further - 'nicor' was Anglo-Saxon for monster. The devil-association is derived from ancient Scandinavian folklore: a Nick was mythological water-wraith or kelpie, found in the sea, rivers, lakes, even waterfalls - half-child or man, half-horse - that took delight when travellers drowned. Beginning several hundred years ago both protestant and catholic clergy commonly referred to these creatures, presumably because the image offered another scary device to persuade simple people to be ever god-fearing (".....or Old Nick will surely get you when you next go to the river...") which no doubt reinforced the Nick imagery and its devil association. So too did the notoriety of Italian statesman and theorist, Niccolo Machiavelli (1469-1527) - (who also gave rise to the expression 'machiavellian', meaning deviously wicked). 'Nick' Machiavelli became an image of devilment in the Elizabethan theatre because his ideas were thought to be so heinous. Shakespeare has Mistress Page using the 'what the dickens' expression in the Merry Wives of Windsor, c.1600, so the expression certainly didn't originate as a reference to Charles Dickens as many believe, who wasn't born until 1812. Charles Dickens' fame however (he was extremely famous in England while alive and writing as well as ever since) would certainly have further reinforced the popularity of the 'dickens' expression.
