diligent

adjective

dil·​i·​gent ˈdi-lə-jənt 

: characterized by steady, earnest, and energetic effort : painstaking

a diligent worker

Many hours of diligent research were required.

Even those who are diligent about using sunscreen every day will still likely experience some unprotected exposure to the sun, such as getting in and out of the car.

—Nick Blackmer

Even the most diligent among us are not immune to the need for a little study break every now and then.

—Alyssa Longobucco

diligently adverb

Did you know?

You’re more likely to be diligent about something if you love doing it. The etymology of diligent reflects the fact that devotion can lead to energetic effort. The word, which entered English in the 14th century by way of Anglo-French, comes from the Latin verb diligere, meaning “to value or esteem highly” or “to love.” Diligere was formed by combining the di- prefix (from dis-, meaning “apart”) with the verb legere, meaning “to gather, select” or “to read.” Legere has itself proved to be a diligent contributor to English; its offspring include collect, lecture, legend, intelligent, and legume.

Synonyms of diligent

• engaged
• busy
• employed
• assiduous
• active

Choose the Right Synonym for diligent

busy, industrious, diligent, assiduous, sedulous mean actively engaged or occupied.

busy chiefly stresses activity as opposed to idleness or leisure.

too busy to spend time with the children

industrious implies characteristic or habitual devotion to work.

industrious employees

diligent suggests earnest application to some specific object or pursuit.

very diligent in her pursuit of a degree

assiduous stresses careful and unremitting application.

assiduous practice

sedulous implies painstaking and persevering application.

a sedulous investigation of the murder

Examples of diligent in a Sentence

The American intelligence community's single greatest failing is its lack of good "humint"—human intelligence, the dirty, diligent, shoe-leather penetration of terror networks. —Johanna McGeary, Time, 15 Oct. 2001

Like any diligent foreign correspondent, he attends the briefings and collects face time with the officials, but he knows it's the citizens … who tell the truth … —Rolling Stone, 19 Sept. 1996

He was a fourth-year drama student at UCLA and diligent about such valuable actorly exercises as eavesdropping, spying, and telling complicated lies to fellow passengers on airplanes. —Michael Chabon, A Model World and Other Stories, 1991

In spite of diligent work as editor, hack writer, sea captain, and assorted other trades, he wound up poor. —Monroe K. Spears, American Ambitions, 1987

a student who has been unceasingly diligent in pursuit of a degree in mathematics

Recent Examples on the Web

Even diligent collateral checks aren’t foolproof, and determined fraudsters will succeed for a while. —Liz Hoffman, semafor.com, 30 Oct. 2025

For those who are still in therapy, being diligent and consistent with your treatment plan is extremely important for reducing long-term risk. —Marnie Goodfriend, Flow Space, 27 Oct. 2025

Meaning, his sons balance a hearty rotation of sports and academics, but the Farrers are also diligent about working in time for volunteer projects, too. —Maggie Menderski, Louisville Courier Journal, 26 Oct. 2025

Help recognize those keeping Anaheim beautiful Here is an opportunity to compliment and recognize your neighbors for their diligent work on maintaining their property. —Andrea Manes, Oc Register, 23 Oct. 2025

Word History

Etymology

Middle English, from Anglo-French, from Latin diligent-, diligens, from present participle of diligere to esteem, love, from di- (from dis- apart) + legere to select — more at legend

First Known Use

14th century, in the meaning defined above

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Kids Definition

diligent

adjective

dil·​i·​gent ˈdil-ə-jənt 

: showing steady and earnest care and effort : painstaking

a diligent search

a diligent worker

diligently adverb