Ignoring their tiresome humming (he likened himself in his imagination to one of the suitors of the Maiden of Mátsaki, unmoved and persistent among the winged vermin), the Savage dug at what was to be his garden.
There are no more uses of "persistent" in the book.
Show samples from other sources
She has a persistent cough.
It is the kind of problem that can be solved if we are persistent in our efforts.