Pronunciation: (nāl'bī"ting),[key] —n. 1. the act or practice of biting one's fingernails, esp. as the result of anxiety or nervousness.
2. Informal.nervousness: The announcement that the trade agreement had been signed ended a week of nail-biting on Wall Street.
—adj. Informal.causing nervousness: The nail-biting part of the canoe trip was through the stretches of white water.