1844 — Anonymous, Edith Leslie, T. C. Newby (1844), page 55:
"Show me a more beautiful creature than the race-horse," added Barrett, "a more noble and thoroughpaced animal than the hunting-horse!"
1859 — Elizabeth Caroline Grey, The Old Country House, Routledge, Warne, & Routledge (1859), page 55:
I, who found it hard matter to keep up my less thoroughpaced steed with the speed of her perfect little Pegasus, […]
1963 — Katherine Anne Porter, The Leaning Tower and Other Stories, Dell (1963), page 13:
He had been a fine, thorough-paced horse once, but he was now a weary, disheartened old hero, gray-haired on his jaw and chin, who spent his life nuzzling with pendulous lips for tender bits of grass […]
Adjective: "extensively trained or schooled; knowledgeable; proficient"
1800 — Anonymous, "Account of the Author", in Robert Burton, The Anatomy of Melancholy, J. Cundee (1800), page xvi:
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. […]
1847 — "The Emerald Studs", Blackwood's Edinburgh Magazine, August 1847, page 218:
And certainly, if the indictment contained a true statement of the facts, James M'Wilkin, or Wilkinson, or Wilson was about as thoroughpaced a marauder as ever perambulated a common.
The thoroughpaced disciples of Filmer, indeed, maintained that there was no difference whatever between the polity of our country and that of Turkey, […]
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.
Look at it how I might, this business wore a most curst aspect, to be sure; nor could I regard myself as anything but a thoroughpaced rogue.
1901 — Louis Becke, Tessa, Unwin Brothers (1901), Chapter VI:
Hendry made no answer to the second mate's remarks, which were accompanied by a considerable number of oaths and much vigorous blasphemy; for the honest-hearted Atkins detested both his captain and the supercargo most fervently, as a pair of thoroughpaced villains.
1901 — Henry A. Beers, A History of English Romanticism in the Nineteenth Century, Henry Holt and Company (1901), page 349:
[…] but Swinburne was perhaps the first thoroughpaced disciple of the French romantic school.
A more thoroughpaced small coquette than La Femme Incomprise never breathed, yet she must needs be a holy angel for the time being to Paul Armstrong, because she had fine eyes and teeth, and could talk with some eloquence about heart-sorrows she had never known.
Sometimes the State, under a strong man like Morton, or James Stewart, Earl of Arran (a thoroughpaced ruffian), put down these pretensions of the Church.