diddycoy
Originally a Romani term of respect (dadika) for an older person, this has come to mean (in UK English) a Gypsy or traveller who is not of pure blood. The insult is therefore compounded, not only does this person have the negative qualities that prejudice has associated with travellers, but they are also of suspect descent, doubly damned.
they're not even proper gyppos, they're fucking diddikois