Antonyms of verb de-energise

1 sense of de-energise

Sense 1
de-energize, de-energise -- (deprive of energy)
       Antonym of energise (Sense 2)
      => stimulate, arouse, brace, energize, energise, perk up -- (cause to be alert and energetic; "Coffee and tea stimulate me"; "This herbal infusion doesn't stimulate")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb de-energise

1 sense of de-energise

Sense 1
de-energize, de-energise -- (deprive of energy)
       => weaken -- (lessen the strength of; "The fever weakened his body")