Definition of "pertinaciously"

Saint Augustine makes this difference betweene an heretike, and him that beleeves an heretike. The first begets or followes an errour pertinaciously.

1601, William Barlow, A defence of the articles of the Protestants religion, Article 3, Answer, page 72

They shall therefore suffer punishment who reject this heavenly Light, and continue pertinaciously fix'd in those deadly principles which extinguish all knowledge of Virtue.

1701, John LeClerc, edited by Samuel Buckley, The Harmony of the Evangelists, London, page 62

No astronomical fallacy is more untenable, and none has been more pertinaciously adhered to, than that of the absolute illimitation of the Universe of Stars.

1848 March, Edgar A[llan] Poe, Eureka: A Prose Poem, New York, N.Y.: Geo[rge] P[almer] Putnam, of late firm of “Wiley & Putnam,” […], page 100

I work with might and main against his Immigration Bill—as pertinaciously and as vindictively, indeed, as he works against our University.

1873, Mark Twain [pseudonym; Samuel Langhorne Clemens], Charles Dudley Warner, chapter XLII, in The Gilded Age: A Tale of To-day, Hartford, Conn.: American Publishing Company, published 1874

If the great comedian [Charlie Chaplin] wishes to stay here in the country whose citizenship he has so pertinaciously retained, he will be less harassed and very welcome.

1952 September 29, “Names Make News: Charlie Chaplin”, in Time‎, New York, N.Y.: Time Inc., archived from the original on 2010-11-25

In Greater Poland (Wielkopolska) the middle class and part of the local gentry clung pertinaciously to Lutheranism.

September 2001, Waldemar Kowalski, “Converts to Catholicism and Reformed Franciscans in Early Modern Poland”, in Church History, volume 70, number 3, page 495