Antonyms of adv grammatically

1 sense of grammatically

Sense 1
grammatically -- (in a grammatical manner; "this child already speaks grammatically")
       Antonym of ungrammatically (Sense 1)
      => ungrammatically -- (in an ungrammatical manner; "this child speaks ungrammatically")

Synonyms of adv grammatically

1 sense of grammatically

Sense 1
grammatically -- (in a grammatical manner; "this child already speaks grammatically")