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

Green mangoes Like green bananas, green (unripe) mangoes offer resistant starch, antioxidants, and significantly less sugar than their ripe, orange counterparts. —Dr. Steven Gundry, CNBC, 21 Nov. 2025

Sweet dumpling squash contains many antioxidants, including phenolic compounds and carotenoids like beta-carotene. —Jillian Kubala, Health, 21 Nov. 2025

Key Takeaways Lightly stir-frying broccoli helps maintain higher levels of sulforaphane, a beneficial antioxidant. —Maggie O'Neill, Verywell Health, 21 Nov. 2025

The echinacea plant is packed with potent antioxidants, and contains a wide net of compounds that are thought to help reduce free radicals and combat inflammation in the body, says Megan Ramaika, a bariatric dietitian at Medstar Washington Hospital Center. —Caroline C. Boyle, USA Today, 21 Nov. 2025

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