Antonyms of adv optionally

1 sense of optionally

Sense 1
optionally -- (in an optional manner; "this rule is applied optionally")
       Antonym of obligatorily (Sense 1)
      => obligatorily -- (in an obligatory manner; "this rule applies obligatorily")

Synonyms of adv optionally

1 sense of optionally

Sense 1
optionally -- (in an optional manner; "this rule is applied optionally")