All optionally antonyms
op·tion·al
O o adverb optionally
- unintentionally — not intentional or deliberate: an unintentional omission from the list.
- forced — strained, unnatural, or affected: a forced smile.
- involuntarily — not voluntary; independent of one's will; not by one's own choice: an involuntary listener; involuntary servitude.
- obligatory — required as a matter of obligation; mandatory: A reply is desirable but not obligatory.
- indispensably — absolutely necessary, essential, or requisite: an indispensable member of the staff.
- necessarily — by or of necessity; as a matter of compulsion or requirement: You don't necessarily have to attend.
- unavoidably — unable to be avoided; inevitable: an unavoidable delay.