A tramp (the UK word for bum or homeless person) who happens to also be a right wanker, for example, because he blatently throws litter onto the pavement in-front of your eyes, or kicks/throws empty cans/bottles into the road, or wanders into the road without looking while you are driving along. In short, a combination of 'tramp' and 'wanker' that rolls easily off the tongue.
What is Sheffield coming to Phillip? I ask you... I mean, just look at that trampker over there, he's not even got any socks on and it's freezing today... what a cock-end. I hate tramps, don't you? And as you said yourself about a month ago, his crotch probably stinks to high heaven, the mucky Arab!