A child who doesn't know how to use the words please, thankyou, or sorry. Who comands adults to do things - and when you say 'what's the magic word' or 'what should you say' or 'you need to say please' just looks at you blankly. Who doesn't understand the word NO - and repeats things till they either get their own way (with parents) or drive another child to losing their temper, and then goes and tells Mummy or Daddy that child X has been nasty to them.
Who won't behave in other people's houses, and parents do nothing. When out and about, interferes with another child's pushchair and toys without asking, takes food off other people's plates (including strangers) without asking. Who wanders off when they feel like it, without telling their parents who then blame other people for not keeping an eye on their child. Who thinks that they can use other people's possessions as if they are their own, and that what they say goes and the world revolves around them.
And strangely enough it does, because if one parent vaguely tries to enforce a rule, the other one pops up and starts pandering to their every whim. Then they go too far - like smashing an ashtray in a open air cafe - ignoring the "No [darling] No, put it down" and lobbing it as hard as possible. And then howls in shock because her parents finally get angry.
You can tell I spent a week on holiday with a family with a spoilt little monster ;-) And am bitter because the next week I couldn't get served in the same cafe!
To me material things are irrelevant - its all about the attitude - basically a lack of awareness, empathy or respect for other people, and everything being all about them. I equate spoilt pretty much to being selfish and ill mannered.
Oh and I blame the parents completely for pandering to them - DD told this kid repeatedly (broken record player technique) "Please stop rocking my chair" - kid kept on doing it. DD eventually held her hand out like a traffic warden and said "X, STOP". So X claimed DD was nasty to her, despite three adults being present at same table. So parent, said "Don't worry X, come and rock my chair, if she won't let you". X says make her apologise to me. To avoid a stand up row about their inadequate parenting in a cafe, I told DD to say "I am sorry you are crying, but I kept asking you to stop rocking my chair and you chose not to listen to me. I don't want you to rock my chair." She repeated it verbatim, turned round to me and said - did I get it right 
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