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Synonyms

rigorous

American  
[rig-er-uhs] / ˈrɪg ər əs /

adjective

  1. characterized by rigor; rigidly severe or harsh, as people, rules, or discipline.

    rigorous laws.

    Synonyms:
    unyielding, stiff, inflexible, hard, austere, stern
    Antonyms:
    soft, flexible
  2. severely exact or accurate; precise.

    rigorous research.

    Synonyms:
    finical, demanding
    Antonyms:
    inaccurate
  3. (of weather or climate) uncomfortably severe or harsh; extremely inclement.

    Synonyms:
    bitter, hard
    Antonyms:
    mild
  4. Logic, Mathematics. logically valid.


rigorous British  
/ ˈrɪɡərəs /

adjective

  1. characterized by or proceeding from rigour; harsh, strict, or severe

    rigorous discipline

  2. severely accurate; scrupulous

    rigorous book-keeping

  3. (esp of weather) extreme or harsh

  4. maths logic (of a proof) making the validity of the successive steps completely explicit

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What does rigorous mean? Rigorous is used to describe things characterized by rigor—strict discipline or severe exactness and precision. Describing an experiment or study as rigorous means it was conducted with extreme precision in order to achieve accuracy. Describing an athletic or academic program as rigorous means it is designed to be challenging and focused on strict discipline. If a teacher is known for being rigorous, it means that they are very strict about things like students completing all of their work and following the rules exactly. Example: The are the result of months of rigorous testing.

Related Words

See strict.

Other Word Forms

Etymology

Origin of rigorous

First recorded in 1350–1400; Middle English, from Medieval Latin rigōrōsus; see rigor, -ous

Explanation

If you are rigorous when you do something, you do it extremely carefully and precisely. A rigorous inspection of your tax records has revealed the government owes you money. Congratulations! The Latin root for rigorous is rigor, meaning “stiffness.” This might remind you of rigor mortis, the stiffening of a body after death, as often seen on cop shows. This is a good, if creepy, way of remembering the meaning of rigorous: rigorous people are stiff and unbending about the standards of their work. This requires being alive, of course.

Keep Reading on Vocabulary.com

Vocabulary lists containing rigorous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Rigorous AI governance that integrates bias testing, transparency and explainability are part of the effort from the start.

From The Wall Street Journal • May 5, 2026

Rigorous checking in the form of visiting their official websites, searching for the person’s name and number online and checking with a representative you’ve previously worked with are all ways to vet for the truth.

From Salon • Feb. 9, 2025

"Rigorous methods exist that can help identify teeth with high accuracy. Our results suggest the presence of spinosaurs, mid-sized tyrannosaurs and tiny dromaeosaurs -- Velociraptor-like theropods -- in these deposits."

From Science Daily • Dec. 5, 2024

Rigorous medical policies and protocols should be enforced by governing bodies and soccer leagues to promote change, she says.

From Scientific American • Jul. 18, 2023

Rigorous tree-thinking demands that a complicated phrase behave in the same way as a simpler phrase in the same position.

From "The Sense of Style" by Steven Pinker