Reactive
WordNet
adjective
(1) Participating readily in reactions
"Sodium is a reactive metal"
"Free radicals are very reactive"
(2) Tending to react to a stimulus
"The skin of the geriatric is less reactive than that of younger persons"- Louis Tuft
WiktionaryText
Adjective
reactive
- that reacts or responds to a stimulus
- that readily takes part in reactions
- francium is the most reactive of the alkali metals.
- Characterized by induction rather than capacitance.
- Reacting to the past rather than anticipating the future, not predictive.