fine line

American  

[fahyn lahyn] / ˈfaɪn ˈlaɪn /

noun

1. a small, barely perceptible difference.

   There's often a fine line between helping and interfering.

---

idioms

1. walk a fine line,

   1. to act carefully in order to avoid the wrong outcome or maintain a delicate balance.

      Moderators walk a fine line between censorship and protecting their site's users.

      I had to walk a fine line between maintaining the peace and doing my job.

   2. to act in a way that risks a disastrous outcome.

      You’re walking a fine line, buddy—if you don’t start watching your mouth, you’ll lose the respect of your kids.

Etymology

Origin of fine line

First recorded in 1845–50

Example Sentences

Olympic coach, John Wroblewski, tells her, “Find that fine line, don’t get in trouble, don’t do anything stupid.”

From The Wall Street Journal • Feb. 16, 2026

There is a fine line between success and failure in winter sports, where a few millimetres when landing difficult tricks on snow can make the difference between a medal or serious injury.

From BBC • Feb. 5, 2026

There is a fine line between humility and confidence, but he said he can get a glimpse of that balance in the way candidates talk about their accomplishments.

From MarketWatch • Jan. 23, 2026

Seoul has for decades trodden a fine line between China, its top trading partner, and the United States, its chief defence guarantor.

From Barron's • Jan. 4, 2026

One of the first things I learned in the hood is that there is a very fine line between civilian and criminal.

From "Born a Crime: Stories from a South African Childhood" by Trevor Noah