reactive /riˈæktɪv/ adjective Learner's definition of REACTIVE
1
[more reactive; most reactive] : done in response to a problem or situation : reacting to problems when they occur instead of doing something to prevent them回应的;反应的 — compare proactive 2
chemistry : tending to change into something else when mixed with another substance易起化学反应的;化学性质活泼的;活性的