As is commonly the case in new areas of research, workplace bullying researchers and practitioners have struggled to establish a single agreed-upon definition of this phenomenon. As a consequence, there are numerous definitions of workplace bullying currently in use around the world to investigate this serious workplace issue, to educate the workforce about this form of harassment and to assess claims involving allegations of workplace bullying. Additionally, little is known about how employees and people in general define workplace bullying behaviour, and whether current researcher, practitioner and legal definitions coincide with lay definitions of bullying. To compare researcher, practitioner and legal definitions of workplace bullying with lay definitions, the content of definitions composed by adults from diverse personal and professional backgrounds (N = 1095) was analysed. Results confirmed that components commonly used by researchers and practitioners, including the occurrence of harmful and negative workplace behaviours, were frequently cited by participants as central defining components of bullying behaviour. In addition, lay definitions often included themes of fairness and respect. The emergence of these themes has important consequences for organisations responding to, and attempting to prevent the occurrence of workplace bullying behaviour in that organisations in which bullying is tolerated may violate both local laws as well as their ethical responsibility to provide employees with a safe, professional and respectful workplace.