facultative

/ˈfæ.kəl.tə.tɪv/

sifat adjective

Of or relating to faculty, especially to mental faculty
Not obligate; optional, discretionary or elective
That grants permission or power to do something
Able to perform a particular life function, or to live generally, in more than one way

Manbalar: Wiktionary (Free Dictionary API orqali), Datamuse, Tatoeba (CC BY 2.0 FR), MyMemory.