Adjective: reactive ree'ak-tiv
- (physics) participating readily in reactions
"sodium is a reactive metal"; "free radicals are very reactive"
- Reacting to a stimulus
"the skin of old persons is less reactive than that of younger persons";
- responsive
See also: labile, oxidisable [Brit], oxidizable, sensitive, thermolabile, unstable
Antonym: unreactive
Encyclopedia: Reactive