strike out vs strikeout

strike out is not a noun while strikeout is a noun.

Word	Noun	Adjective	Verb	Adverb
strike out	No	No	Yes	No
strikeout	Yes	No	No	No

strike out (noun)	strikeout (noun)
	an out resulting from the batter getting three strikes

strike out (verb)	strikeout (verb)
set out on a course of action
remove from a list
cause to get out
put out or be put out by a strikeout
make a motion as with one's fist or foot towards an object or away from one's body
be unsuccessful in an endeavor