The state, or an act, of stubbornness or doggedness.
He finished only through a mixture of determined obstinacy and ingenuity.
1877, Leo Tolstoy (author), David Magarshack (translator), Anna Karenina, part 6, ch 12,
His hand closed, he drew back, and his face assumed a still more stubborn expression.
"For you it's a matter of obstinacy," she said, looking intently at him and suddenly finding the right word for the expression of his face which exasperated her so much.
(countable, collective) A group of bison; the collective noun for bison.