thor·​ough | \ ˈthər-(ˌ)ō How to pronounce thorough (audio) , sometimes ˈthȯr-; ˈthə-(ˌ)rō \

Essential Meaning of thorough

1 : including every possible part or detail a thorough investigation/search a thorough [=complete] examination a thorough understanding of the rules and regulations
2 : careful about doing something in an accurate and exact way : meticulous a thorough worker The investigator will have to be thorough.
3 chiefly British : complete or absolute a thorough disgrace a thorough mess/nuisance

Full Definition of thorough

 (Entry 1 of 3)

1 : carried through to completion : exhaustive a thorough search
2a : marked by full detail a thorough description
b : careful about detail : painstaking a thorough scholar
c : complete in all respects thorough pleasure
d : having full mastery (as of an art) a thorough musician



Definition of thorough (Entry 2 of 3)




Definition of thorough (Entry 3 of 3)


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Other Words from thorough


thoroughness noun

Examples of thorough in a Sentence

Adjective … one realized that it was the restaurant's thorough and even comic Frenchness that had made it so entirely New York. — Adam Gopnik, New Yorker, 22 Mar. 2004 Bruce tells me to squat down and Koani sidles up, ears flattened, tail tucked away, and gives my face a thorough licking. — Nicholas Evans, Daily Telegraph, 26 Sept. 1998 The job was uncharacteristically thorough for a Russian contract killing—three different types of bullets riddled Mikho's body. New Republic, 15 Dec. 1997 a thorough understanding of the rules and regulations The investigator will have to be thorough.
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Recent Examples on the Web: Adjective An arbitrator for the Sports Resolution Centre of Canada ruled that an investigation of her harassment claims was inadequate and incomplete and ordered a more thorough investigation to take place. Los Angeles Times, 4 Oct. 2021 What Letitia James, New York’s attorney general, did was exactly what those of us who are victims and survivors have been calling for: a thorough investigation. Camila Falquez, Harper's BAZAAR, 27 Sep. 2021 Over the past 11 months and two weeks, Brystal's office had turned into the center of a thorough investigation. Lacey Vorrasi-banis,, 24 Sep. 2021 And those who planned and executed the family separation policy have still not been held to account, despite Biden's promise of a thorough investigation. Jill Filipovic, CNN, 23 Sep. 2021 This includes a thorough investigation, possible suspension, recommendation for placement in an alternative setting and possible referral to local law enforcement. Dallas News, 16 Sep. 2021 Organizations looking for a more thorough reset can bring in an occupational clinician to give a third-party view on current practices, and where approaches can be updated or revamped. Claire Schmidt, Forbes, 1 Oct. 2021 The issue of missing women and questions over whether the police had conducted thorough investigations have dogged Indigenous communities in the United States for decades. New York Times, 30 Sep. 2021 The city of Anaheim was ordered Monday to perform a new and more thorough search of public records requested by the citizens’ group seeking to invalidate the Angel Stadium land sale. Bill Shaikin, Los Angeles Times, 27 Sep. 2021

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

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First Known Use of thorough


15th century, in the meaning defined at sense 1


before the 12th century, in the meaning defined above


before the 12th century, in the meaning defined above

History and Etymology for thorough

Preposition, Adjective, and Adverb

Middle English thorow, from Old English thurh, thuruh, preposition & adverb

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Time Traveler for thorough

Time Traveler

The first known use of thorough was before the 12th century

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Dictionary Entries Near thorough




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Statistics for thorough

Last Updated

15 Oct 2021

Cite this Entry

“Thorough.” Dictionary, Merriam-Webster, Accessed 27 Oct. 2021.

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More Definitions for thorough


thor·​ough | \ ˈthər-ō How to pronounce thorough (audio) \

Kids Definition of thorough

1 : being such to the fullest degree : complete a thorough search
2 : careful about little things a thorough worker

Other Words from thorough

thoroughly adverb
thoroughness noun

More from Merriam-Webster on thorough

Nglish: Translation of thorough for Spanish Speakers

Britannica English: Translation of thorough for Arabic Speakers


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