challenging

• For the most part, they're challenging--a good thing if that's what you want to read--but challenging is like a steady diet of vegetables. —  Magazine - Aeon Authors - 2006 - Issue 06 - Aeon Six
• Walking this line between observer and participant is challenging, and the consequences of it should be obvious if you look at what happened on Wall Street, where analysts were paid significant sums of money in order to not only observe the system but also to game it. —  O'Reilly News: XML
• We knew then that the environment for such a sale would be challenging, as indeed it has proven to be. —  Romenesko
• I'm talking about the legacy Pinter leaves as one of the most challenging -- and dare I say it? —  Entertainment Weekly's PopWatch
• According to Kelly Services (M) Sdn Bhd vice-president and country general manager Melissa Norman, another challenging issue is the mismatch of skill sets: "It is imperative that the skills gap in the local workforce be addressed urgently."

Allen's Synonyms and Antonyms

Word Family