Knife-edge and Nail-biting

Knife-edge noun - A narrow boundary.

Nail-biting and knife-edge are semantically related. In some cases you can use "Nail-biting" instead an adjective phrase "Knife-edge".

Nail-biting adjective - Marked by or causing agitation or uncomfortable feelings.

Knife-edge and nail-biting are semantically related. Sometimes you can use "Knife-edge" instead an adjective phrase "Nail-biting".