This study examined definitions and concepts of cyberbullying. It identified words, terms and definitions used for negative acts on the internet and mobile phones across different age groups in the United Kingdom. Young people and adults' (N = 32; age = 8–54) constructs and perceptions of negative online behaviours were also reported. Focus groups and individual interviews were employed using qualitative triangulation: Thematic Analysis and Interpretative Phenomenological Analysis. The study examined current definitions and concepts of cyberbullying and how these differ in its findings; and considered different ways to foster positive online behaviour for the context of practitioners. The concept of cyber-aggression is used to describe a wide range of behaviours other than cyberbullying. The findings indicate that there is a need to include a broader definition in line with the current trend of a range of behaviours that are common with internet and mobile phone usage.