A perjorative word used to describe travellers, originally a corruption of the Romani phrase "Dik a dai", meaning "look at this"
Bloody hell, the diddycoys have syphoned off my diesel and stolen my batteries!
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
First used as an insult against poor Irish immigrants to Britain.
Now used to refer to people more commonly described as gippos
Tell the diddycoy we don't want anymore pegs dear.