erstwhile

1 of 2

adverb

erst·​while ˈərst-ˌ(h)wī(-ə)l 

: in the past : formerly

… cultures, erstwhile unknown to each other …

—Robert Plank

erstwhile

2 of 2

adjective

: former, previous

erstwhile enemies

Did you know?

The adverb erstwhile has been part of English since at least the 16th century, but it is formed from two words that are much older. It comes from the Old English words aer, meaning "early," and hwil, which has the same meaning as the modern word while. (The English word ere, meaning "before," is also a descendant of aer.) These days erstwhile is more likely to be encountered as an adjective, as in "erstwhile enemies." That adjective use is a much more recent development, having joined the language about three centuries after the adverb.

Synonyms of erstwhile

Adverb

• formerly
• once

Adjective

• former
• old
• other

Examples of erstwhile in a Sentence

Adverb

there's now a store where erstwhile lay green and pleasant pastures

Adjective

my erstwhile friend ignored me when I ran into her at the reunion

Recent Examples on the Web

Adverb

Candidates for the fifth spot include former postseason hero Ian Anderson, erstwhile All-Star Bryce Elder, and rookies AJ Smith-Shawver and Hurston Waldrep. After winning a surprise world championship in 2021, the Braves had two 100-win seasons without reaching the final round again. —Dan Schlossberg, Forbes, 10 Dec. 2024

In South Africa’s middle class suburban areas, including Randburg, where there’s more visible policing, lockdown measures are being tightly enforced, leaving several erstwhile busy stalls and shopping areas empty. —Quartz Africa, 4 Apr. 2020

Adjective

The thieves made off with nine items of jewelry belonging to members of France's erstwhile royal families. —Jamie Gray, NBC news, 21 Oct. 2025

The erstwhile president and his entourage got on a jet that flew them to Hmeimim, a coastal air base controlled by Russia, which had been his most critical backer in the war. —Danny Makki, New York Times, 16 Oct. 2025

Word History

First Known Use

Adverb

1569, in the meaning defined above

Adjective

1849, in the meaning defined above

Rhymes for erstwhile

• argyle
• awhile
• beguile
• compile
• condyle
• defile
• exile
• freestyle
• gentile
• hairstyle
• lifestyle
• meanwhile

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Kids Definition

erstwhile

1 of 2 adverb

erst·​while ˈərst-ˌ(h)wīl 

: in the past : once, formerly

erstwhile

2 of 2 adjective

: former sense 3, previous