2 synonym groups for Optional

optional, voluntary, discretionary, elective, nonmandatory, facultative, nonobligatory, unrequired, free, open, nonessential, unforced, unprescribed, nonbinding, free-will, free-choice, nonrequisite, nonimperative, noncoercive, nonenforced, noncompelling, nonnecessitated, nonprescribed, nonobliged, nonconstraining, nonrestrictive, noncompulsory [x]

unnecessary, unimportant, trivial, insignificant, minor, peripheral, dispensable, extraneous, superfluous, redundant, noncritical, nonvital, optional, inessential, unneeded, needless, irrelevant, inconsequential, immaterial, secondary, marginal, auxiliary, expendable, nonmandatory, nonobligatory, noncompulsory, nonrequired, noncrucial, nonindispensable, nonimperative, nonurgent, nonparamount, nonpivotal, noncentral, nonfundamental, nonintegral, nonkey, nonprimary, nonprincipal [x]