razor edge vs edge

razor edge and edge both are nouns.

Word	Noun	Adjective	Verb	Adverb
razor edge	Yes	No	No	No
edge	Yes	No	Yes	No

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

razor edge (noun)	edge (noun)
an edge that is as sharp as the cutting side of a razor	a sharp side formed by the intersection of two surfaces of an object
	the outside limit of an object or area or surface; a place farthest away from the center of something
	a slight competitive advantage
	the attribute of urgency in tone of voice
	the boundary of a surface
	a line determining the limits of an area

razor edge (verb)	edge (verb)
	lie adjacent to another or share a boundary
	provide with an edge
	advance slowly, as if by inches
	provide with a border or edge