Antonyms of adj underactive

1 sense of underactive

Sense 1
hypoactive, underactive -- (abnormally inactive)

INDIRECT (VIA inactive) -> active -- (characterized by energetic activity; "an active toddler"; "active as a gazelle"; "an active man is a man of action")

Similarity of adj underactive

1 sense of underactive

Sense 1
hypoactive, underactive -- (abnormally inactive)
       => inactive (vs. active) -- (not active physically or mentally; "illness forced him to live an inactive life"; "dreamy and inactive by nature")