lexical ambiguity vs ambiguity

lexical ambiguity and ambiguity both are nouns.

Word	Noun	Adjective	Verb	Adverb
lexical ambiguity	Yes	No	No	No
ambiguity	Yes	No	No	No

As nouns, ambiguity is a hypernym of lexical ambiguity; that is, ambiguity is a word with a broader meaning than lexical ambiguity:

lexical ambiguity: the ambiguity of an individual word or phrase that can be used (in different contexts) to express two or more different meanings
ambiguity: unclearness by virtue of having more than one meaning

Other hypernyms of lexical ambiguity include equivocalness.

lexical ambiguity (noun)	ambiguity (noun)
the ambiguity of an individual word or phrase that can be used (in different contexts) to express two or more different meanings	unclearness by virtue of having more than one meaning
	an expression whose meaning cannot be determined from its context