reactive

adjective

re·​ac·​tive rē-ˈak-tiv 

1

: of, relating to, or marked by reaction or reactance

2

a

: readily responsive to a stimulus

b

: occurring as a result of stress or emotional upset

reactive depression

reactively adverb

reactiveness noun

Examples of reactive in a Sentence

The government's response to the problem was reactive rather than proactive.

Recent Examples on the Web

Dynamic soft robots To create OCTOID’s modular actuating legs, researchers fabricated active (AL) and passive layers (PL) from cholesteric liquid crystal elastomers (CLCEs) using a bottom-up self-assembly of reactive mesogens, crosslinkers, and chain extenders. —Jijo Malayil, Interesting Engineering, 26 Oct. 2025

Combine the two in a non-reactive container and stir. —Jeremy Repanich, Robb Report, 25 Oct. 2025

The temptation to make reactive changes based on small sample sizes is constant. —Karl Moore, Forbes.com, 24 Oct. 2025

These people are all very reactive and very impulsive. —Lexi Carson, HollywoodReporter, 24 Oct. 2025

Word History

First Known Use

1717, in the meaning defined at sense 1

Phrases Containing reactive

• C-reactive protein
• hyper-reactive
• reactive arthritis

Rhymes for reactive

• attractive
• contractive
• extractive
• inactive
• proactive
• refractive
• subtractive
• active
• tractive
• bioactive
• hyperactive
• interactive

Kids Definition

reactive

adjective

re·​ac·​tive rē-ˈak-tiv 

1

: of or relating to reaction

2

: reacting or tending to react

reactively adverb

reactiveness noun

reactivity

(ˌ)rē-ˌak-ˈtiv-ət-ē 

noun

Medical Definition

reactive

adjective

re·​ac·​tive rē-ˈak-tiv 

1

a

: of, relating to, or marked by reaction

reactive symptoms

a reactive process

b

: capable of reacting chemically

highly reactive materials

2

a

: readily responsive to a stimulus

the skin of the geriatric is less reactive than that of younger persons

—Louis Tuft

b

: occurring as a result of stress or emotional upset especially from factors outside the organism

reactive depression