challenge
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.
Social media companies point to under-13s being disallowed from joining their platforms - though questions remain about how strictly this is enforced - and versions of their sites with parental controls when challenged on questions of harm.
From BBC
Planning for a secure retirement is a major challenge.
From MarketWatch
But he sees the tiny startup facing challenges as it scales up.
One of the biggest challenges in cancer care is that the same therapy can be highly effective for some patients yet fail entirely for others.
From Science Daily
This discovery not only challenges existing ideas in fundamental physics but may also serve as a kind of universal connector linking electronics, spintronics, and quantum technologies.
From Science Daily
From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.