verb
- Take exception to.
- usage: "She challenged his claims"
- Issue a challenge to.
- usage: "Fischer challenged Spassky to a match"
- synonyms: challenge
- Ask for identification.
- usage: "The illegal immigrant was challenged by the border guard"
- synonyms: challenge
- Raise a formal objection in a court of law.
- synonyms: challenge, take exception
adjective
- Requiring full use of your abilities or resources.
- usage: "ambitious schedule"; "performed the most challenging task without a mistake"
- synonyms: ambitious
- Stimulating interest or thought.
- usage: "a challenging hypothesis"; "a thought-provoking book"
- synonyms: thought-provoking
- Disturbingly provocative.
- usage: "an intriguing smile"
- synonyms: intriguing