Antonyms of adv efficiently

1 sense of efficiently

Sense 1
efficiently, expeditiously -- (with efficiency; in an efficient manner; "he functions efficiently")
       Antonym of inefficiently (Sense 1)
      => inefficiently -- (in an inefficient manner; "he dealt inefficiently with the crisis")

Synonyms of adv efficiently

1 sense of efficiently

Sense 1
efficiently, expeditiously -- (with efficiency; in an efficient manner; "he functions efficiently")