(STRENGTH) [noun] [U] - the power and ability to be physically and mentally activeSince I started eating more healthily, I've felt so full of energy.The children were bursting with energy.I was going to go out this evening, but I haven't got the energy.These days I just seem to lack the energy to do anything. [+ to infinitive](approving) We need someone with energy (= eagerness) and enthusiasm to do this job.(approving) Her writing is full of passion and energy (= enthusiasm).
Meaning of ENERGY in English
Cambridge English vocab. Кембриджский английский словарь. 2012