noun
voluntariness; voluntary nature; optionality
Abstract noun referring to the quality of being voluntary, optional, or at one's discretion. Often used in legal, philosophical, or technical contexts.
この制度の参加は任意性が高い。
Participation in this system is highly voluntary.
契約の任意性について議論する。
We discuss the voluntary nature of the contract.
随意 also means 'voluntary' or 'optional', but is often used in formal or legal contexts. 任意性 is more about the inherent nature of being voluntary.
Compound of 任意 (にんい, 'voluntary, optional') + 性 (せい, '-ness, -ity'), forming an abstract noun meaning 'voluntariness' or 'optionality'.