thorough
Americanadjective
-
executed without negligence or omissions.
a thorough search.
- Synonyms:
- total, unqualified, sheer, downright, exhaustive, in-depth
- Antonyms:
- superficial, partial
-
thorough enjoyment.
-
extremely attentive to accuracy and detail; painstaking: a thorough analysis.
a thorough worker;
a thorough analysis.
-
having full command or mastery of an art, talent, etc..
a thorough actress.
-
extending or passing through.
adverb
noun
adjective
-
carried out completely and carefully
a thorough search
-
(prenominal) utter
a thorough bore
-
painstakingly careful
my work is thorough
noun
Other Word Forms
Etymology
Origin of thorough
First recorded before 900; Middle English (preposition and adverb); Old English thuruh, variant of thurh through
Explanation
Thorough describes something that is painstakingly complete, like a thorough search for your missing keys in which you look for them in coat pockets, under the table, in the refrigerator — in every single place you can think of. Thorough rhymes with "burrow": "THUR-oh." It looks a lot like through but remember thorough is an adjective, so you might use it to describe a thorough investigation or a thorough review. In contrast through is used most often as a preposition — you might look through every drawer, for example, in a search — or as an adverb — you might see a hole in your pocket where coins fall through.
Vocabulary lists containing thorough
"Earth and Space"
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Harry Potter and the Prisoner of Azkaban
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“Whilst the event provided both a helpful and thorough review of the business outlook as well as a strategic refresh, it was met with a fairly punishing market response.”
From The Wall Street Journal ● Sep. 22, 2026
"I am optimistic that the report is going to be thorough, will raise criticisms, and will hopefully result in some real change," she said.
From BBC ● Sep. 12, 2026
Still, Rabat called the crisis "regrettable" and said the events warranted "a thorough examination" to establish their circumstances and "ensure that they do not happen again".
From Barron's ● Sep. 10, 2026
The next time my mother tells me that something does not feel right, I will make sure her work-up is thorough and her screenings—the ones that the current evidence recommends—are current.
From Slate ● Sep. 9, 2026
Why was she so obsessively thorough in her documentation?
From "The Girl Who Drew Butterflies: How Maria Merian's Art Changed Science" by Joyce Sidman
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"Thorough culling" to reduce the number of bears is the only effective way to reduce the risk for local people, researcher Ohnishi said.
From Barron's ● Nov. 8, 2025
Thorough cooking of any freshwater fish that could potentially be infected can prevent illness, according to the U.S.
From Los Angeles Times ● Jun. 4, 2025
Thorough clinical trials have already proven benefits to heart health - and nausea is a known side-effect - but other findings will need to go through similar rigorous testing.
From BBC ● Jan. 20, 2025
Thorough background checks have long been a norm used by incoming presidents when choosing their Cabinet.
From Salon ● Nov. 25, 2024
Miss Foldal allowed that her aunt had been an old lady of strong views; all the same, she was of opinion that Thorough must be Mr. Harper's motto.
From The Sailor by J. C. Snaith
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.