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

This highly reactive chemical can inflame our lungs, causing muscles to constrict and making breathing painful, according to the Environmental Protection Agency. — Kasha Patel, CNN Money, 17 July 2026

The researchers’ measurements indicate that gamma radiation passing through the surrounding air produces reactive molecules that subtly alter the ribbon edges without changing their overall structure. — Prabhat Ranjan Mishra, Interesting Engineering, 17 July 2026

There are plenty of competing considerations for brands and retailers looking to navigate new sourcing waters, and a reactive approach could have considerable impacts throughout the supply chain. — Kate Nishimura, Footwear News, 17 July 2026

But when cost-cutting is the primary lens, AI adoption can become reactive instead of strategic. — Ryan McMillen, Forbes.com, 17 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