English Reference
adjective

rigorous

adj.
US /ˈɹɪɡɝəs/ UK /ɹˈɪɡəɹəs/ rig·or·ous

  1. 01 B2 Upper Intermediate Academic

    very careful and detailed to make sure everything is correct.

    characterised by scrupulous accuracy and attention to detail; adhering strictly to a set of standards or methods.

    Simple

    The scientists conducted a rigorous test to make sure the new medicine was safe.

    In context

    The peer-review process for the journal is exceptionally rigorous, ensuring that only the most methodologically sound research reaches publication.

    Usage

    Often used to describe research, testing, analysis, or training.

  2. 02 B2 Upper Intermediate

    strict and following the rules exactly, often in a way that is difficult.

    strictly applied or enforced; demanding high levels of discipline or effort.

    Simple

    The army has a rigorous training program for new soldiers.

    In context

    The academy maintains rigorous standards of conduct, and students who fail to comply are often asked to leave.

  3. 03 C1 Advanced Literary

    very difficult or unpleasant to live through, like a cold winter.

    harsh, severe, or extremely inclement, particularly in reference to weather or living conditions.

    Simple

    The explorers had to survive a rigorous winter in the mountains.

    In context

    The expedition was ill-prepared for such a rigorous climate, lacking the specialised equipment necessary to endure sub-zero temperatures for months.

Usage appreciation rigorous · merit rigorous · rigorous analysis

He called for rigorous scientific research to show whether it would be both safe and effective.

The Guardian· 19 Aug 2026

I chose someone independent, rigorous and fearless, the best in Australia, because that is what this job demands.

The Guardian· 20 Aug 2026

Inherited from Middle English rigorous, from Middle French and Anglo-Norman rigoreus, derived from Late Latin rigōrōsus (stiff, rigid; inflexible). By surface analysis, rigor + -ous.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin la-lat rigōrōsus
Level B2 · Upper Intermediate
Frequency Frequent
Updated