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

Those plump little gems are juicy, sweet, and packed with antioxidants and fiber. —Katie Rosenhouse, Southern Living, 25 Feb. 2026

The formula also includes holy basil extract, which contains antioxidants to protect against environmental stress. —Sarah Felbin, Allure, 25 Feb. 2026

That's because of its high content of catechins, which are polyphenol antioxidants. —Angelica Bottaro, Verywell Health, 25 Feb. 2026

Strawberries and blueberries are packed with antioxidants and fiber, supporting heart health without causing major blood sugar spikes. —Emily Cegielski, Flow Space, 25 Feb. 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