nondiscretionary

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective nondiscretionary is

not discretionary; thus, frequently, mandatory.

As a verb spending

is .

As a noun spending

is an amount that has been, or is planned to be spent.

As an adjective nondiscretionary is

not discretionary; thus, frequently, mandatory.

As adjectives the difference between mandatory and nondiscretionary

is that mandatory is obligatory; required or commanded by authority while nondiscretionary is not discretionary; thus, frequently, mandatory.

As a noun mandatory

is a person, organisation or state who receives a mandate; a mandatary.