madcap vs impetuous

madcap is a noun but impetuous is not a noun.

Word	Noun	Adjective	Verb	Adverb
madcap	Yes	Yes	No	No
impetuous	No	Yes	No	No

As adjectives, madcap and impetuous are synonyms defined as:

madcap and impetuous: characterized by undue haste and lack of thought or deliberation

Other synonyms of madcap include brainish, hotheaded, impulsive, tearaway.

madcap (noun)	impetuous (noun)
a reckless impetuous irresponsible person

madcap (adjective)	impetuous (adjective)
characterized by undue haste and lack of thought or deliberation	marked by violent force
	characterized by undue haste and lack of thought or deliberation