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

In addition to pure retinol, which helps reduce the appearance of fine lines and wrinkles, this unique product features retinyl palmitate, an antioxidant-rich skin protectant, as well as retinyl acetate, a natural form of vitamin A that keeps pores clean while stimulating collagen production. —Michelle Baricevic, InStyle, 14 Jan. 2026

Oats contain natural plant compounds, including certain antioxidants called avenanthramides. —Alexandria Nyembwe, Health, 14 Jan. 2026

Lowers Cancer Risk Compounds, such as antioxidants, in kombucha may help protect against cancer. —Julie Marks, Verywell Health, 14 Jan. 2026

According to Salazar, the drink contains antioxidants, including catechins such as epigallocatechin-3-gallate (EGCG). —Kirsten Nunez, Martha Stewart, 13 Jan. 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