strange vs unknown

strange is not a noun while unknown is a noun.

Word	Noun	Adjective	Verb	Adverb
strange	No	Yes	No	No
unknown	Yes	Yes	No	No

As adjectives, strange and unknown are synonyms defined as:

strange (noun)	unknown (noun)
	a variable whose values are solutions of an equation
	an unknown and unexplored region
	anyone who does not belong in the environment in which they are found

strange (adjective)	unknown (adjective)
being definitely out of the ordinary and unexpected; slightly odd or even a bit weird	not known
relating to or originating in or characteristic of another place or part of the world	being or having an unknown or unnamed source
not known before	not famous or acclaimed
	not known before
	not known to exist