Antonyms of adv officially

1 of 2 senses of officially

Sense 1
officially -- (in an official role; "officially, he is in charge"; "officially responsible")
       Antonym of unofficially (Sense 2)
      => unofficially -- (not in an official capacity; "unofficially, he serves as the treasurer")

Synonyms of adv officially

2 senses of officially

Sense 1
officially -- (in an official role; "officially, he is in charge"; "officially responsible")

Sense 2
formally, officially -- (with official authorization; "the club will be formally recognized")