a fine line

a fine line

A very narrow division between two deceptively similar things, one of which is worse than the other. As a new parent, you learn that there's a fine line between looking out for your child's welfare and being overprotective. A: "I only borrowed your sweater, I swear!" B: "Well, it's a fine line between borrowing and stealing, isn't it?"
See also: fine, line

a fine line between something

COMMON If there is a fine line between two different activities or situations, there is a point at which they are very similar, often when one activity or situation is acceptable, and the other is not. There is a fine line between being nicely looked after and being fussed over too much. A new exhibition explores the fine line between genius and insanity. Note: You can also talk about a thin line between two things or a narrow line between two things. There is a thin line between being a good player and being one of the best. There's a narrow line between being interested and being nosy. Compare with walk a fine line between something.
See also: between, fine, line, something
References in periodicals archive ?
"We may be regarded as underdogs and I would rather we were not but there is such a fine line between success and failure at this level and we will have to beat the Italians to have a realistic chance of making the last eight."
A WORD OF CAUTION There's a fine line between being a reliable, in-charge chica and being an overbearing, bossy control freak[