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

The researchers found strong deposits of 3-nitrotyrosine, a molecular marker associated with cellular damage caused by reactive oxygen species. — Melissa Cristina Márquez, Forbes.com, 1 Aug. 2026

He’s become consumed by trying to solve theatrical lighting—essentially, creating ultra-cheap audience-reactive lightshows for coffee shops and small venues. — Kieran Press-Reynolds, Pitchfork, 30 July 2026

This includes Techfit that is enhanced with reactive Rheon polymers. — Arthur Zaczkiewicz, Footwear News, 27 July 2026

The data collected by these robots can be filtered and transmitted to operators in real time, allowing companies to identify problems earlier and shift from reactive repairs toward predictive maintenance. — Jijo Malayil, Interesting Engineering, 27 July 2026

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

• active
• tractive
• attractive
• contractive
• extractive
• inactive
• proactive
• refractive
• subtractive
• 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