Antonyms of adj lethargic

1 sense of lethargic

Sense 1
lethargic (vs. energetic), unenrgetic -- (deficient in alertness or activity; "bullfrogs became lethargic with the first cold nights")

energetic (vs. lethargic) -- (possessing or exerting or displaying energy; "an energetic fund raiser for the college"; "an energetic group of hikers"; "it caused an energetic chemical reaction")
        => physical -- (characterized by energetic bodily activity; "a very physical dance performance")
        => alert, brisk, lively, merry, rattling, snappy, spanking, zippy -- (quick and energetic; "a brisk walk in the park"; "a lively gait"; "a merry chase"; "traveling at a rattling rate"; "a snappy pace"; "a spanking breeze")
        => canty -- (lively and brisk)
        => driving -- (acting with vigor; "responsibility turned the spoiled playboy into a driving young executive")
        => high-energy -- (providing a relatively large amount of energy upon undergoing a chemical reaction)
        => indefatigable, tireless, unflagging, unwearying -- (showing sustained enthusiastic action with unflagging vitality; "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence")
        => strenuous -- (characterized by or performed with much energy or force; "strenuous exercise")
        => vigorous -- (characterized by forceful and energetic action or activity; "a vigorous hiker"; "gave her skirt a vigorous shake"; "a vigorous campaign"; "a vigorous foreign policy"; "vigorous opposition to the war")

Similarity of adj lethargic

1 sense of lethargic

Sense 1
lethargic (vs. energetic), unenrgetic -- (deficient in alertness or activity; "bullfrogs became lethargic with the first cold nights")
       => dazed, foggy, groggy, logy, stuporous -- (stunned or confused and slow to react (as from blows or drunkenness or exhaustion))
       => dreamy, lackadaisical, languid, languorous -- (lacking spirit or liveliness; "a lackadaisical attempt"; "a languid mood"; "a languid wave of the hand"; "a hot languorous afternoon")
       => listless -- (lacking zest or vivacity; "he was listless and bored")
          Also See-> inactive#9