reactivePronunciation: /rɪˈaktɪv/Definition of reactive adjective 1showing a response to a stimulus:pupils are reactive to light Physiology showing an immune response to a specific antigen: lysosomal activity can activate B lymphocytes reactive against self-components (of a disease or illness) caused by a reaction to something:reactive arthritis reactive depression having a tendency to react chemically:nitrogen dioxide is a highly reactive gas 2acting in response to a situation rather than creating or controlling it:a proactive rather than a reactive approach 3 Physics relating to reactance:a reactive loadreactive in other Oxford dictionaries Definition of reactive in the US English dictionary
