vis (force, emphasis): virtus: vigor (life and spirit, both of animate and inanimate things): gravitas (weight, energy of words, etc., verborum, sententiarum): fervor (heat): acrimonia (pungent or stinging energy, rare): impetus (energy attack in a speech, aliter in oratione nec impetus ullus nec vis esse potest, Cic.): robur: nervi (strength of mind, energy of character). Anything requires all your energy of character, aliquid tuorum est nervorum (Cic.). The energy of a speaker, virtus oratoris: vis oratoris, dicentis: virtus oratoria: with something of energy, cum quadam virtute. What energy there is in that book! quantum in illo libro vigoris est! (Sen.) A man of energy, vir fortis, acer.