deciding vs determinative

deciding and determinative both are nouns.

Word	Noun	Adjective	Verb	Adverb
deciding	Yes	Yes	No	No
determinative	Yes	Yes	No	No

As adjectives, deciding and determinative are synonyms defined as:

Other synonyms of deciding include determinant, determining.

deciding (noun)	determinative (noun)
the cognitive process of reaching a decision	a determining or causal element or factor
	one of a limited class of noun modifiers that determine the referents of noun phrases

deciding (adjective)	determinative (adjective)
having the power or quality of deciding	having the power or quality of deciding