as·​sid·​u·​ous | \ ə-ˈsij-wəs How to pronounce assiduous (audio) , -ˈsi-jə- \

Definition of assiduous

: showing great care, attention, and effort : marked by careful unremitting attention or persistent application assiduous planning an assiduous book collector She tended her garden with assiduous attention.

Other Words from assiduous

assiduously adverb
assiduousness noun

Choose the Right Synonym for assiduous

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

Did you know?

Judges presiding over assizes (former periodical sessions of the superior courts in English counties) had to be assiduous in assessing how to best address their cases. Not only were their efforts invaluable, but they also serve as a fine demonstration of the etymologies of assiduous, assess, and assize. All three of those words derive from the Latin verb assidēre, which is variously translated as "to sit beside," "to take care of," or "to assist in the office of a judge." Assidēre, in turn, is a composite of the prefix ad- (in this case, meaning "near" or "adjacent to") and sedēre, meaning "to sit."

The History of Assiduous

Assiduous came to English directly from the Latin assiduus, an adjective derived from the verb assidēre "to sit beside." To the ancient Romans, assiduus carried meanings ranging from “settled or rooted in place” to “constantly present” to “persistent, unremitting." This last sense was the one borrowed into English four hundred years ago and still used today, often in complimentary phrases such as "an assiduous student" and “assiduous efforts.” In the 18th century, the word took on a mildly pejorative meaning, "obsequious," when used of someone striving to please. This sense has largely passed out of use.

Examples of assiduous in a Sentence

They were assiduous in their search for all the latest facts and figures. The project required some assiduous planning.
Recent Examples on the Web Digitally savvy Ukrainians have been assiduous in their fight to bring Russians to justice for war crimes. Dominique Soguel, The Christian Science Monitor, 10 June 2022 In the end, rather than convincing us that Chernobyl was a typical nuclear accident, Mr. Plokhy’s assiduous account shows that the disaster was the product of a uniquely corrupt and inhumane political system. James B. Meigs, WSJ, 20 May 2022 The administration's assiduous efforts to ease supply chain backups at ports and internal transportation hubs can help only at the margins. John Harwood, CNN, 1 Apr. 2022 Outsider Pictures is an assiduous distributor of Spanish-language films. Justin Morgan, Variety, 10 Mar. 2022 Both paintings combine aspects of stylized illustration—industrial clouds of smoke, slanting rain—with painterly effects and an investigation of reality at once intermittent and assiduous. Garth Greenwell, The New Yorker, 15 Feb. 2022 Finkelstein attacked the route with an assiduous efficiency. Zach Helfand, The New Yorker, 31 Jan. 2022 This moniker implied moral imperatives, ethical perfection and assiduous attention to putting patients first. Shakeel Ahmed, Forbes, 5 Nov. 2021 Altogether, the assiduous weight-saving regimen has the P1 tipping the scales at 3,076 pounds. Robert Ross, Robb Report, 8 Nov. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'assiduous.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of assiduous

circa 1552, in the meaning defined above

History and Etymology for assiduous

Latin assiduus, from assidēre to sit beside

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Time Traveler for assiduous

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The first known use of assiduous was circa 1552

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Last Updated

30 Jun 2022

Cite this Entry

“Assiduous.” Dictionary, Merriam-Webster, Accessed 6 Jul. 2022.

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More Definitions for assiduous


as·​sid·​u·​ous | \ ə-ˈsi-jə-wəs How to pronounce assiduous (audio) \

Kids Definition of assiduous

: showing great care, attention, and effort They were assiduous in gathering evidence.

Other Words from assiduous

assiduously adverb

More from Merriam-Webster on assiduous

Nglish: Translation of assiduous for Spanish Speakers

Britannica English: Translation of assiduous for Arabic Speakers


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