nail-biter

(noun) a situation that causes a lot of uncertainty and tension

Example Sentences:

Last week’s election was a nail-biter, because both of the candidates had 50% of the vote.

A: How was your weekend?
B: It was a nail-biter, because my father was in the hospital.

Our team won the match with 30 seconds left. What a nail-biter of a victory!!

From the News:

Leafs eliminate Islanders in nail-biter

Media:

Similar idioms:

1. hit the nail on the head
2. nail it