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

The ones that have earned a rightful long-term place in my quiver are the ones that obsess over seam taping, stress test their zippers, and refine fabrication choices with rigorous field testing. —Todd Plummer, Robb Report, 25 Feb. 2026

In the 2024-25 school year, nearly 60,000 LAUSD students enrolled in an AP class, which is a rigorous, standardized, college-level course. —Christopher Buchanan, Los Angeles Times, 25 Feb. 2026

Unapproved peptides haven’t undergone the rigorous clinical trials that would be needed to prove their effectiveness. —Dominique Mosbergen, Time, 24 Feb. 2026

Every credit card story is based on rigorous reporting by our team of expert writers and editors. —Jason Stauffer, CNBC, 24 Feb. 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