English Reference
adjective

curious

adj.
US /ˈkjʊɹiəs/ UK /kjˈʊɹɪəs/ cu·ri·ous

  1. 01 B1 Intermediate

    wanting to know or learn about something.

    eager to know or learn something; possessing a desire for investigation or information.

    Simple

    The curious child asked her teacher why the sky was blue.

    In context

    The researchers remained curious about the long-term effects of the treatment, leading them to extend the study for another five years.

    Usage

    often followed by the preposition 'about' or an infinitive verb.

    Teacher's tip

    While usually positive, it can occasionally imply being 'nosy' if the person is asking too many personal questions.

  2. 02 B2 Upper Intermediate

    strange, unusual, or unexpected.

    arousing interest by being unusual, strange, or unexpected.

    Simple

    It was curious that the front door was open when I arrived home.

    In context

    The detective found it curious that the witness remembered the exact time of the event but could not describe the suspect's clothing.

    Usage

    often used in the phrase 'it is curious that...'

    Teacher's tip

    In this sense, the word describes the object or situation, not the person observing it.

Usage curious kids

I encourage clients to get curious about it, rather than trying to fight it.

The Guardian· 19 Aug 2026

Fortunately, for journalists, researching questions we’re curious about is part of the job.

Smithsonian Magazine· 17 Jun 2026

Etymology 1

From Middle English curious, from Old French curius, from Latin cūriōsus. The English word is cognate with Italian curioso, Occitan curios, Portuguese curioso, and Spanish curioso.

Etymology 2

From curi(um) + -ous.

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

This entry
Origin Latin cūriōsus
Level B2 · Upper Intermediate
Frequency Common
Updated