a knife edge

Translations
лезвие ножа
The knife edge was dull and needed sharpening.
Лезвие ножа было тупым и нуждалось в заточке.
Definitions
A knife edge refers to a very sharp or finely honed edge, often used metaphorically to describe a situation that is precarious or finely balanced, where small changes can lead to significant consequences.
Words
a

article or possessive pronoun
неопределённый артикль
knife

noun
нож
edge

noun
край