imposing vs noble

imposing is not a noun while noble is a noun.

Word	Noun	Adjective	Verb	Adverb
imposing	No	Yes	No	No
noble	Yes	Yes	No	No

As adjectives, imposing and noble are synonyms defined as:

Other synonyms of imposing include baronial, stately.

imposing (noun)	noble (noun)
	a titled peer of the realm

imposing (adjective)	noble (adjective)
used of a person's appearance or behavior; befitting an eminent person	having or showing or indicative of high or elevated character
impressive in size, manner, or appearance	of or belonging to or constituting the hereditary aristocracy especially as derived from feudal times
	impressive in size, manner, or appearance
	inert especially toward oxygen