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
always used before a noun chiefly British
: complete or absolute
a thorough disgrace
a thorough mess/nuisance
Cite this Entry
“Thorough.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/thorough. Accessed 23 Apr. 2026.
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