My 4 year old is a very clever little girl, just recently she has started saying things like I was going to call u stupid mummy but I didn't or I don't love u/daddy/sibling (just a few examples as there are lots of others seemingly designed to get a reaction).I've tried talking to her about it and I've tried ignoring her. This morning she said I have a fat tummy (meaning me, which unfortunately s true ) 
I'm really upset about this. I want to really tell her off but I know this will make it worse so i've tried to ignore it, she said it again a few minutes after. She has never heard the word fat in our house, I won't allow anyone to discuss diets when she is around even to the point where the word is spelt out. She can only have heard it at nursery, which I am very sad about. She sad a man was fat in a restaurant the other day, I was mortified and tried calmly to explain that saying that was mean, it hurts feelings, would she want her feelings hurt etc which obviously hasn't worked. Is this normal? I'm really upset and worried about this. She has her share of Whiney, defiant nightmarish 4 year old behaviour which can be awful. She starts school in September so I'm hoping this will help. I am trying to be a lot tougher on her as she was being very naughty a few weeks ago, this has got slightly better but she can still be very challenging. What should I do?