reactive

To be reactive is to be ready to react or respond to something else — as opposed to ready to act on one's own. A person who's reactive does things only in response to others.

To react is to do something in response to something else. When someone pinches you, for example, you react. But if you're a reactive person, then you only react; you're always ready to react but not to act on your own. You're rather lifeless unless something or someone else causes you to do act. This is usually seen as a negative trait in people, unless you're talking about, say, firefighters or cops. We admire people who don't need prodding to get things done. Some chemicals are called reactive, too, because they react readily with other chemicals.

DEFINITIONS OF: reactive

1

adj participating readily in reactions

“sodium is a reactive metal”
“free radicals are very reactive
Synonyms
activated, excited
(of e.g. a molecule) made reactive or more reactive
labile
(chemistry, physics, biology) readily undergoing change or breakdown
oxidizable
capable of undergoing a chemical reaction with oxygen
thermolabile
(chemistry, physics, biology) readily changed or destroyed by heat
unstable
highly or violently reactive
Antonyms:
unreactive
(chemistry) not reacting chemically
inactive
(chemistry) not participating in a chemical reaction; chemically inert
indifferent, inert, neutral
having only a limited ability to react chemically; chemically inactive
noble
inert especially toward oxygen
stable
not taking part readily in chemical change
show more antonyms...

adj reacting to a stimulus

“the skin of old persons is less reactive than that of younger persons”
Synonyms:
responsive
sensitive
responsive to physical stimuli
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