English dictionary

optional

/'/A/p/S//@/n/-/l/

Definitions, examples, synonyms and antonyms from WordNet 3.0.

adjective

possible but not necessary; left to personal choice

adj.all

Antonyms obligatory

Source: WordNet 3.0
Involving an option; depending on the exercise of an option; left to one's discretion or choice; not compulsory; as, <i>optional</i> studies; it is <i>optional</i> with you to go or stay.

adjective

Source: webster1913