silver bullet vs solution

silver bullet and solution both are nouns.

Word	Noun	Adjective	Verb	Adverb
silver bullet	Yes	No	No	No
solution	Yes	No	No	No

As nouns, solution is a hypernym of silver bullet; that is, solution is a word with a broader meaning than silver bullet:

silver bullet (noun)	solution (noun)
a simple guaranteed solution for a difficult problem	the successful action of solving a problem
	a method for solving a problem
	a statement that solves a problem or explains how to solve the problem
	the set of values that give a true statement when substituted into an equation
	a homogeneous mixture of two or more substances; frequently (but not necessarily) a liquid solution