Antonyms of adv unintentionally

1 sense of unintentionally

Sense 1
unintentionally, accidentally -- (without intention; in an unintentional manner; "she hit him unintentionally")
       Antonym of intentionally (Sense 1)
      => intentionally, deliberately, designedly, on purpose, purposely, advisedly, by choice, by design -- (with intention; in an intentional manner; "he used that word intentionally"; "I did this by choice")

Synonyms of adv unintentionally

1 sense of unintentionally

Sense 1
unintentionally, accidentally -- (without intention; in an unintentional manner; "she hit him unintentionally")