1
: very strict and demanding
rigorous enforcement of the rules
rigorous training
a rigorous course of study
2
: done carefully and with a lot of attention to detail
We subjected the data to a rigorous analysis.
a rigorous investigation
3
: difficult to endure because of extreme conditions
a harsh, rigorous climate
Cite this Entry
“Rigorous.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/rigorous. Accessed 19 Jun. 2026.
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