knife-edge vs limit

knife-edge and limit both are nouns.

Word	Noun	Adjective	Verb	Adverb
knife-edge	Yes	No	No	No
limit	Yes	No	Yes	No

As nouns, limit is a hypernym of knife-edge; that is, limit is a word with a broader meaning than knife-edge:

Other hypernyms of knife-edge include bound, boundary.

knife-edge (noun)	limit (noun)
a narrow boundary	the greatest possible degree of something
	the boundary of a specific area
	as far as something can go
	the greatest amount of something that is possible or allowed
	the mathematical value toward which a function goes as the independent variable approaches infinity
	final or latest limiting point

knife-edge (verb)	limit (verb)
	restrict or confine within limits
	place limits on (extent or amount or access)
	decide upon or fix definitely