Energetic

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mid 17th century (in the sense ‘powerfully effective’): from Greek energētikos, from energein ‘operate, work in or upon’ (based on ergon ‘work’).

wiktionary

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From New Latin energeticus (16th c.), or its source, Ancient Greek ἐνεργητικός(energētikós), from ἐνεργέω(energéō, “to be active”), from ἐνεργός(energós, “active”).

etymonline

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energetic (adj.)

1650s, "powerful in operation," from Greek energetikos "active," from energein "to work, be in action, act upon" (see energy). Of persons, "active," in English from 1796 (energetical "operative" is from c. 1600; from 1630s as "full of energy," while energical is attested from 1560s). Related: Energetically.