write up vs writing

write up and writing both are nouns.

Word	Noun	Adjective	Verb	Adverb
write up	Yes	No	Yes	No
writing	Yes	No	No	No

write up (noun)	writing (noun)
a short account of the news	the activity of putting something in written form
	the act of creating written works
	the work of a writer; anything expressed in letters of the alphabet (especially when considered from the point of view of style and effect)
	letters or symbols that are written or imprinted on a surface to represent the sounds or words of a language
	(usually plural) the collected work of an author

write up (verb)	writing (verb)
bring to public notice by writing, with praise or condemnation
put into writing; write in complete form