Decisiveness is a related term of purposefulness.
As nouns the difference between decisiveness and purposefulness
is that decisiveness is the state or quality of being decisive while purposefulness is (uncountable) the state of being purposeful.
decisiveness
English
Noun
(-)
The state or quality of being decisive.
purposefulness
English
Noun
(head)
(uncountable) The state of being purposeful.