Endurance (7)
'endurance' is the definition.
(I know that stamina is a type of endurance)
This is all the clue.
(Other definitions for stamina that I've seen before include "Indefatigability" , "capability to keep going" , "Ability for sustained effort" , "Parts of flowers" , "Enduring energy" .)
'endurance' is the definition.
(I know that endurance can be written as survival)
This is the entire clue.
(Other definitions for survival that I've seen before include "Relic from former times" , "The ... of the fittest (Darwinian evolutionary theory)" , "Persistence" , "Continued existence" , "A hangover from a former time" .)