important vs decisive

important and decisive both are adjectives.

Word	Noun	Adjective	Verb	Adverb
important	No	Yes	No	No
decisive	No	Yes	No	No

important (adjective)	decisive (adjective)
of great significance or value	determining or having the power to determine an outcome
of extreme importance; vital to the resolution of a crisis	characterized by decision and firmness
important in effect or meaning	forming or having the nature of a turning point or crisis
having or suggesting a consciousness of high position	unmistakable
having authority or ascendancy or influence