As an adjective facultative
is of or relating to faculty, especially to mental faculty.
As a noun provisional is
a member of the.
Of or relating to faculty, especially to mental faculty
Not obligate; optional, discretionary or elective
That grants permission or power to do something
(biology) Able to perform a particular life function, or to live generally, in more than one way
(geometry, of a point) At which a given function is positive.
Free Medical Dictionary
* Oxford English Dictionary
(philately) a postage stamp issued locally before an official issue is released.