Antonyms for lethargy

laziness, sluggishness:

busyness, action, awakening, activity, energy, wakefulness, liveliness, concern, regard, life, vivacity, vigor, vitality, interest, consciousness, vivaciousness.

noun:

agitation, enterprise, storm, alarm, frenzy, passion, eagerness, care, sympathy, excitement, enthusiasm, anxiety, vivacity, disturbance, vehemence, violence, sensibility, distress, turbulence, susceptibility, feeling, ambition, sensitiveness, keenness, spiritedness, emotion, fury.