Someone who owns items, especially cars, which are far more expensive than other comparable items. This is done in an attempt to look cool, but inevitably involves involves them looking a total tit. Anyone who drives a new Mini Cooper or a BMW is instantly a pretentious git.
Anyone who thinks a conversation about the bodywork, wheels or paintjob on their car is at all interesting is almost certainly a pretentious git. In many countries it is illegal to let such drivers out of side turnings.
"Have you seen that two-tone paintwork on the Mini - what a pretentious git!"
"He might as well paint 'Tiny cock' on the bonnet of his BMW, the pretentious git."