nail biter

noun — 2 senses

nail biter

noun

1

One who habitually bites or chews their fingernails.

But Victor did not reveal any behavior disorder, did not pick his nose, did not suck his thumb, was not even a nail biter.1957 March 7, Vladimir Nabokov, chapter 4.3, in Pnin, Heinemann, page 90:

2

Figuratively A situation which causes anxiety, suspense, nervousness or discomfort.

It was a real nail biter waiting for the test results.
And in a shockingly misogynistic ad, Republicans placed an image of O’Connor in a huddle of three supposedly nightmarish mascots of liberalism, all women: Pelosi, Elizabeth Warren and Hillary Clinton. O’Connor absorbed all of this and still turned the race into a nail-biter.2018 August 8, Frank Bruni, “A Nail-Biter in Ohio Is a Democratic Triumph”, in New York Times:

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.