assurance
audacity
boldness
brashness
bulldog courage
cohesiveness
decisiveness
durability
endurance
energy
fatigue
firmness
force
fortitude
gameness
gaminess
grittiness
guts
gutsiness
haleness
hardihood
hardness
hardship
heartiness
infrangibility
intestinal fortitude
lastingness
leatherlikeness
longevity
lustihood
lustiness
mettlesomeness
might
mightiness
nerve
nerviness
obstinacy
pertinaciousness
pertinacity
pluckiness
potency
power
powerfulness
resistance
resoluteness
resolution
robustness
strength
congeniality
virility