Negative feedback is criticism that has aversive/negative tone. Usually the person receiving the feedback decides if the comment/feedback is negative. It isn't necessarily outrageous because sometimes the feedback really and obviously negative. Even so, sometimes a person simply can't handle constructive criticism well and takes it as negative. Its all about perception, tone, and reaction.
A great way to explain this is through job/career assessments. If your boss says you're analysis report is not good. This is feedback, though it has a less than positive tone and isn't automatically negative. Its just not helpful or useful.
If your boss says your analysis isn't good because their are many errors and spelling mistakes. It is more like constructive and justifiable feedback (though less than positive in tone), based on facts/evidence
If your boss says your analysis isn't because you are a terrible writer and you should quit. That is negative feedback. If its when you feel like it is an attack, or you feel the need to defend yourself or it makes you angry/sad/etc. perhaps it can be negative (even so that could just be an insecure and responsible person reacting insecurely). Sometimes insecure people overreact before understanding the full situation
Even so, if you receive negative feedback you should take in stride and ask questions to clarify what they mean before you react based on emotions. Sometimes people don't know how to say something in a smart way. Sometimes people's choice of words is bad.