reactive

[ ree-ak-tiv ]
/ riˈæk tɪv /

adjective

tending to react.
pertaining to or characterized by reaction.
Electricity. pertaining to or characterized by reactance.

Origin of reactive

First recorded in 1705–15; react + -ive
Related forms
Can be confusedproactive reactionary reactive
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for unreactive (1 of 2)

unreactive

/ (ˌʌnrɪˈæktɪv) /

adjective

(of a substance) not readily partaking in chemical reactions

British Dictionary definitions for unreactive (2 of 2)

reactive

/ (rɪˈæktɪv) /

adjective

readily partaking in chemical reactionssodium is a reactive metal; free radicals are very reactive
of, concerned with, or having a reactance
responsive to stimulus
(of mental illnesses) precipitated by an external causereactive depression
Derived Formsreactively, adverbreactivity (ˌriːækˈtɪvɪtɪ) or reactiveness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unreactive

reactive


adj.

1712, from react + -ive. Related: Reactively; reactiveness; reactivity.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for unreactive

reactive

[ rē-ăktĭv ]

adj.

Tending to be responsive or to react to a stimulus.
Characterized by reaction.
Tending to participate readily in chemical reactions.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.