How do I know whether something counts as bullying or not?

I think something counts as bullying if the person is saying harmful things intentionally. The person can be saying things to purposely put down the other person and making them feel bad about themselves. The person doing the bullying is also aware of the person's triggers or off limit topics and are still progressing with the harmful comments. Overall, there is an intent to cause someone else to feel bad and down about themselves or about a situation. If a person feels they are being bullied, their feelings should be considered valid and the situation should be considered bullying.