outstanding vs striking

outstanding is not a noun while striking is a noun.

Word	Noun	Adjective	Verb	Adverb
outstanding	No	Yes	No	No
striking	Yes	Yes	No	No

As adjectives, outstanding and striking are synonyms defined as:

outstanding and striking: having a quality that thrusts itself into attention

Other synonyms of outstanding include prominent, salient, spectacular.

outstanding (noun)	striking (noun)
	the act of contacting one thing with another
	the physical coming together of two or more things

outstanding (adjective)	striking (adjective)
having a quality that thrusts itself into attention	having a quality that thrusts itself into attention
of major significance or importance	sensational in appearance or thrilling in effect
distinguished from others in excellence
owed as a debt