striking vs outstanding

striking is a noun but outstanding is not a noun.

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

As adjectives, striking and outstanding are synonyms defined as:

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

Other synonyms of striking include prominent, salient, spectacular.

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

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