Definition of "thoroughpaced"

I, who found it hard matter to keep up my less thoroughpaced steed with the speed of her perfect little Pegasus, […]

1859, Elizabeth Caroline Grey, The Old Country House, Routledge, Warne, & Routledge (1859), page 55

[T]he terrors of superior authority were plainly perceivable in his features, and in less than three months he became a thorough-paced husband.

1751, [Tobias] Smollett, The Adventures of Peregrine Pickle […], volumes (please specify |volume=I to IV), London: Harrison and Co., […]

Wood's character of him is, that — "he was an exact mathematician, a curious calculator of nativities, a general read scholar, a thorough-paced philologist, and one that understood the surveying of lands well. […]

1800, Anonymous, "Account of the Author", in Robert Burton, The Anatomy of Melancholy, J. Cundee (1800), page xvi

The improbability of a thoroughpaced scoundrel writing daily elaborate confessions of his criminality to a friend, even when the friend condemns him, expatiating upon atrocities that deserved hanging, and justifying his vices on principle, is rather too glaring to be admissible.

1892, Leslie Stephen, Hours in a Library, Volume I, Smith, Elder, & Co., page 87

[…] but Swinburne was perhaps the first thoroughpaced disciple of the French romantic school.

1901, Henry A. Beers, A History of English Romanticism in the Nineteenth Century‎, Henry Holt and Company, page 349