The passage of health-care reform will suddenly shift from sure-thing to nail-biter.
He'd been a nail-biter when he was a kid, but he'd kicked the habit when we got to high school.
noun
Something very worrying and suspenseful: If Lucas looked this nervous as the Spurs were blowing out the Clippers, how would he react during a nail-biter?/ The gain in compliance cases brought by the SEC has been a nail-biter for brokerage executives (1990s+)