one-year vs annual

one-year is not a noun while annual is a noun.

Word	Noun	Adjective	Verb	Adverb
one-year	No	Yes	No	No
annual	Yes	Yes	No	No

As adjectives, one-year and annual are synonyms defined as:

one-year (noun)	annual (noun)
	a reference book that is published regularly once every year
	(botany) a plant that completes its entire life cycle within the space of a year

one-year (adjective)	annual (adjective)
completing its life cycle within a year	completing its life cycle within a year
	occurring or payable every year