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

According to the authors, this increasingly crowded and competitive environment makes rigorous biosafety standards more urgent than ever. —Leonard David, Space.com, 3 June 2026

France is a country that fastidiously applies rigorous nomenclature to everything from cheese to wine. —Matt Ortile, Condé Nast Traveler, 3 June 2026

Every personal finance article is based on rigorous reporting by our team of expert writers and editors with extensive knowledge of financial products. —Jason Stauffer, CNBC, 3 June 2026

Some current and former students say the pressure often becomes most acute inside the rigorous IB program for 11th- and 12th-graders (and which, as of 2022, included 130 full-diploma students, according to the school’s website). —Théoden Janes, Charlotte Observer, 3 June 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