Definition of "untriumphalist"

To me, he looked not just very tired, but almost as if he was bereaved: as sombre and untriumphalist as in 2008, when he defeated Ken Livingstone.

2012 March 29, Andrew Gimson, Boris: The Adventures of Boris Johnson, Simon and Schuster

"The Surgeon's Daughter" is an imperial text, though a curiously untriumphalist one.

2021 December 28, Configuring Romanticism: Essays offered to C. C. Barfoot, BRILL, page 48

At the end of the Falklands war two years earlier too, the Queen, whose second son, Andrew, had served as a helicopter pilot with the task force, was singularly untriumphalist and showed no inclination to follow her prime minister’s injunction to rejoice at victory.

September 8 2022, Stephen Bates, “Queen Elizabeth II obituary”, in The Guardian‎