rigorous

adjective

rig·​or·​ous ˈri-g(ə-)rəs 

1

: manifesting, exercising, or favoring rigor : very strict

2

a

: marked by extremes of temperature or climate

b

: harsh, severe

3

: scrupulously accurate : precise

rigorously adverb

rigorousness noun

Synonyms of rigorous

• strict
• tough
• harsh
• authoritarian
• rigid
• stern

Choose the Right Synonym for rigorous

rigid, rigorous, strict, stringent mean extremely severe or stern.

rigid implies uncompromising inflexibility.

rigid rules of conduct

rigorous implies the imposition of hardship and difficulty.

the rigorous training of recruits

strict emphasizes undeviating conformity to rules, standards, or requirements.

strict enforcement of the law

stringent suggests severe, tight restriction or limitation.

stringent standards of admission

Examples of rigorous in a Sentence

rigorous enforcement of the rules

a rigorous course of study

We subjected the data to a rigorous analysis.

Recent Examples on the Web

Under 1% leave during the rigorous six-month SEAL Qualification Training course, which is the final leg of the pipeline before they are assigned to a SEAL team. — James Laporta, CBS News, 5 Nov. 2026

Every personal loan review is based on rigorous reporting by our team of expert writers and editors with extensive knowledge of personal loan products. — Dan Avery,jasmin Suknanan, CNBC, 5 Nov. 2026

The agreement capped Iran’s uranium enrichment levels, reduced its operational centrifuge numbers, required Iran to repurpose its nuclear weapons development facilities, and established more rigorous international inspections to verify compliance. — S. C. M. Paine, Foreign Affairs, 3 Nov. 2026

The chemicals subject to the new policy haven’t gone through that rigorous vetting process. — ABC News, 28 Oct. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Rhymes for rigorous

• vigorous

Kids Definition

rigorous

adjective

rig·​or·​ous ˈrig-(ə-)rəs 

1

: very strict

2

: marked by great differences of temperature or climate

3

: very accurate

rigorously adverb

rigorousness noun