The Proto-Indo-European word *wéihₓ(e)s-
Word *wéihₓ(e)s-
Meaning vitality, strength, vital force
See also Proto-Indo-European: *weihₓ- ‘to be strong’
Synonyms *bel-, *h₂eiw-, *hₐénr̥, *hₐóyus, *wór(hₓ)ĝs, *hₐeuges-

Comments
Mallory J.P. and Adams D. (2006)