zest for life

:  a piece of the peel of a citrus fruit (such as an orange or lemon) used as flavoring

:  an enjoyably exciting quality :  piquancy

:  keen enjoyment :  relish, gusto

:  the quality that distinguishes a vital and functional being from a dead body

:  a principle or force that is considered to underlie the distinctive quality of animate beings

:  an organismic state characterized by capacity for metabolism (see metabolism 1), growth, reaction to stimuli, and reproduction

:  of or relating to animate being

:  lifelong

:  using a living model