work out vs workout

work out is not a noun while workout is a noun.

Word	Noun	Adjective	Verb	Adverb
work out	No	No	Yes	No
workout	Yes	No	No	No

work out (noun)	workout (noun)
	the activity of exerting your muscles in various ways to keep fit

work out (verb)	workout (verb)
do physical exercise
give a workout to
come up with
work out in detail
find the solution to (a problem or question) or understand the meaning of
make a mathematical calculation or computation
be calculated
happen in a certain way, leading to, producing, or resulting in a certain outcome, often well