Challenging [verb]

Education, the "backbone" of cultural activities, is one of the most challenging current problems facing Virginia.

He stands for the famous Hohenzollern, challenging eyes, full lips, retroussé mustache and imperious air.

Noticeable above all were Perrette and Yolande, the former always brazen and challenging.

"Lead the way up that hill and you'll find out," she answered with a challenging flash of her dark eyes.

"I don't see why they shouldn't have him," said Edward Henry, as he lifted a challenging nose in the air.

Franz was at the evening meal with his family when he heard Caesar's challenging roar.

Again as the light broadened the dogs were loosed and presently were challenging all four points of the compass.

His eyes opened; they were the wild, bright eyes, reckless and challenging, of Fighting Conal.

We even hear of William challenging Harold to decide the dispute by single combat.

Without a thought they began a sort of challenging rencounter with horse-artillery and cavalry.