progressive (adj): a word used by socialists, liars and politicians* to conceal their real agenda, i.e. increased statism, a reduction in personal liberties and a massive increase of tax.
Ideally, this tax increase should fall most heavily upon the poor as they must then approach the state in order to beg for some of their meagre earnings to be returned to them in the form of Tax Credits and other benefits, thus creating a client population who will always vote for more statism, particularly in the form of those dishonest bastards** currently in charge.
There, that's fairly comprehensive, no?
* Apologies for the tautology.