indefatigability

Your mastery of the language, and your indefatigability, would make you infinitely useful in any of these departments.

It is as if, for all his physical robustness, he has not quite the spiritual indefatigability of the major artist.

His indefatigability infected his comrades, they became more eager the longer the struggle lasted.

No painter ever copied himself with more constancy and indefatigability.

It is because of my own indefatigability in talking about talk about talk that they made me a Knight.