Article of interest: 'Rude Vs. Mean Vs. Bullying: Defining The Differences' copy and paste the link to your browser: https://www.huffpost.com/entry/bullying_n_2188819
Rude = Inadvertently saying or doing something that hurts someone else. Mean = Purposefully saying or doing something to hurt someone once (or maybe twice). Bullying = Intentionally aggressive behaviour, repeated over time, that involves an imbalance of power.