Thesaurus <span class="searchmatch">optional</span> discretionary elective facultative free noncompulsory nonmandatory nonobligate nonobligatory nonrequired nonrequisite <span class="searchmatch">optional</span> optionary...
intrinsic [⇒ thesaurus] dispensable gratuitous inessential needless <span class="searchmatch">optional</span> [⇒ thesaurus] unnecessary unneeded “630. requirement” in Roget's Thesaurus...
involuntary mandatory nonoptional obligatory required unbewised unvoluntary <span class="searchmatch">optional</span> [⇒ thesaurus] advised encouraged recommended suggested Thesaurus:command...
dodgeable escapable evadable evitable fleeable nonmandatory nonobligatory <span class="searchmatch">optional</span> [⇒ thesaurus] preventable preventible resistible skippable inevitable ...
unagreeable unconsenting unwilling Thesaurus:inclined Thesaurus:obey Thesaurus:<span class="searchmatch">optional</span> “488. assent” in Roget's Thesaurus, T. Y. Crowell Co., 1911. “602. willingness”...