GJP is a term basically meaning 'shit' or 'shitty' usually used when talking about sketty girls or generally people who get around a lot.
Also good for using when refering to someone who lies all the time about really bad things or talks a lot of rubbish.
A habbitual liar.
Also a term for someone who bleeds their friends and loved ones dry at any available opportunity. Much like a leech, once all resources have been used they will move on.
Originated somewhere between Tidworth and Salisbury.
'stop talking such GJP'
'she's a proper GJP girl'
'I wouldnt go near her, she'll GJP all over you'
'I wouldnt listen to anything they say, all that comes out of their mouth is a load of GJP'
'I heard she'd won the lottery...what a steaming heap of GJP'
'you are so GJP'