thorniness vs thorny

thorniness is a noun but thorny is not a noun.

Word	Noun	Adjective	Verb	Adverb
thorniness	Yes	No	No	No
thorny	No	Yes	No	No

thorniness (noun)	thorny (noun)
the quality of being covered with prickly thorns or spines
a rough and bitter manner
The property of being full of difficulties, complexities, or controversial points.

thorniness (adjective)	thorny (adjective)
	having or covered with protective barbs or quills or spines or thorns or setae etc.
	bristling with perplexities