fitness

noun

1. (uncountable, usually)The condition of being fit, suitable or appropriate.

   “Having introduced my two characters separately, let me present them together. Why not? He, young, wealthy, honorable; she also young, also intelligent — why not bring them together? There is an eternal fitness in all things, and nothing more so than in the case of man and woman.”

   “That's chiefly why they're coming; I want you to meet them here and then tell me frankly what you think of their fitness for whatever we decide on doing.”

2. (uncountable, usually)The cultivation of an attractive and/or healthy physique.

   “Carroll has been edging slowly towards full fitness after his expensive arrival from Newcastle United and his partnership with £23m Luis Suarez showed rich promise as Liverpool controlled affairs from start to finish.”

3. (uncountable, usually)An organism's or species' degree of success in finding a mate and producing offspring.
4. (UK, slang, uncountable, usually)The condition of being attractive, fanciable or beautiful.