antioxidant

noun

an·​ti·​ox·​i·​dant ˌan-tē-ˈäk-sə-dənt 

ˌan-ˌtī-

: a substance (such as beta-carotene or vitamin C) that inhibits oxidation or reactions promoted by oxygen, peroxides, or free radicals

antioxidant adjective

Examples of antioxidant in a Sentence

Recent Examples on the Web

By correcting the imbalance between free radicals and antioxidants (referred to as oxidative stress), the polyphenols may improve arterial function and help ease blood pressure. —Md Published, Verywell Health, 28 Apr. 2026

The spice's active compound, curcumin, is a potent anti-inflammatory and antioxidant that can help support a range of ailments and conditions. —Lindsay Curtis, Health, 28 Apr. 2026

It’s also packed with antioxidants and has a 12% moisture level. —Bestreviews, Mercury News, 27 Apr. 2026

The bulk of these benefits is due to antioxidants known as polyphenols, which have anti-inflammatory properties, says Lauren Slayton, MS, RD. —Embry Roberts, Martha Stewart, 25 Apr. 2026

Word History

First Known Use

1919, in the meaning defined above

Rhymes for antioxidant

• oxidant

Kids Definition

antioxidant

noun

an·​ti·​ox·​i·​dant ˌant-ē-ˈäk-səd-ənt 

ˌan-ˌtī-

: a substance that opposes oxidation or prevents or makes difficult reactions made easier by oxygen

Medical Definition

antioxidant

noun

an·​ti·​ox·​i·​dant ˌant-ē-ˈäk-səd-ənt, ˌan-ˌtī- 

: any of various substances (as beta-carotene, vitamin C, and alpha-tocopherol) that inhibit oxidation or reactions promoted by oxygen and peroxides and that include many held to protect the living body from the deleterious effects of free radicals

antioxidant adjective