"Determinableness" is a word in ENGLISH

Capable of being decided by arbitration; determinable.

Fitted to be a subject of judicial investigation; capable of being judicially heard and determined.

Capable of being decided; determinable.

Capable of being defined, limited, or explained; determinable; describable by definition; ascertainable; as, definable limits; definable distinctions or regulations; definable …

Capable of being determined, definitely ascertained, decided upon, or brought to a conclusion.

A proposition affirming the possibility of finding such conditions as will render a certain determinate problem indeterminate or capable of …

Capable of being determined beforehand.

The attribute of being so much, and not more or less; the property of being measurable, or capable of increase …

Capable of self-determination; as, the self-determining power of will.