"Reactive" refers to a response or action that occurs as a result of an external stimulus or event. In various contexts, such as chemistry or psychology, it describes how entities respond to changes in their environment. For example, a chemical reaction is considered reactive when substances interact due to changes in temperature or pressure. In everyday life, being reactive can mean responding to situations as they arise rather than planning ahead. For instance, a reactive person may handle problems only when they occur, rather than anticipating and preventing them. This approach can lead to quick solutions but may also result in missed opportunities for proactive planning.