incidental vs resultant

incidental and resultant both are nouns.

Word	Noun	Adjective	Verb	Adverb
incidental	Yes	Yes	No	No
resultant	Yes	Yes	No	No

As adjectives, incidental and resultant are synonyms defined as:

Other synonyms of incidental include accompanying, attendant, collateral, concomitant, consequent, ensuant, sequent.

incidental (noun)	resultant (noun)
an item that is incidental	a vector that is the sum of two or more other vectors
(frequently plural) an expense not budgeted or not specified	something that results
	the final point in a process

incidental (adjective)	resultant (adjective)
(sometimes followed by `to') minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence	occurring with or following as a consequence
not of prime or central importance
occurring with or following as a consequence