facultative
[adjective]
Synonyms: optional, discretionary, elective, non-obligatory

[TahlilGaran] English Synonym Dictionary ▲

facultative adjective. ['fak(ǝ)ltǝtɪv] E19.
[French facultatif, -ive, from faculté: see FACULTY, -ATIVE.]
1. Permissive; optional; contingent. E19.
b. attrib. in Biology. Capable of but not restricted to a particular (specified) function, mode of life, etc. Opp. OBLIGATE adjective 2. L19.

2. Of or pertaining to a faculty. M19.

[TahlilGaran] English Dictionary ▲