impulsiveness vs impulsive

impulsiveness is a noun but impulsive is not a noun.

Word	Noun	Adjective	Verb	Adverb
impulsiveness	Yes	No	No	No
impulsive	No	Yes	No	No

impulsiveness (noun)	impulsive (noun)
the trait of acting suddenly on impulse without reflection

impulsiveness (adjective)	impulsive (adjective)
	determined by chance or impulse or whim rather than by necessity or reason
	having the power of driving or impelling
	characterized by undue haste and lack of thought or deliberation
	proceeding from natural feeling or impulse without external stimulus
	without forethought