(n.) Substance or quality of temperament; spirit, courage, fortitude\, ardor, etc.; disposition; -- usually in a good sense.

activity animation animus aptitude ardor backbone bent bias bottom brio briskness cast character chutzpah constitution courage dauntlessness diathesis disposition eccentricity elan enthusiasm gameness glow grain grit gusto guts gutsiness guttiness heart heart of oak idiosyncrasy impetuosity impetus inclination individualism intestinal fortitude joie de vivre kidney leaning life liveliness lustiness make makeup mental set mettlesomeness mind mind-set mold moxie nature nerve perkiness pertness pith pluck pluckiness predilection predisposition preference proclivity propensity resolution robustness set slant spirit spiritedness spunk spunkiness stamina stamp stout heart strain streak stripe temper temperament tendency toughness true grit turn turn of mind twist type vivacity warmth warp zest zestfulness