grave affair

"This is a grave affair, in which the intention to establish an espionage network in Israel for Iran was exposed," a Shin Bet statement said, without listing the charges against the group.

From Reuters ● Jan. 12, 2022

"This is a grave affair, and we cannot jump at conclusions."

From The Boy Scouts of the Eagle Patrol by John Henry Goldfrap

A revolution, your Reverence, among the Americanos, with robbery of the Presidio saluting-gun; a grave affair.

From The Crusade of the Excelsior by Bret Harte

Really, instinct ought to teach 99her better whom to make her confident as respected that grave affair.

From Aurora the Magnificent by Gertrude Hall Brownell

The Chinese who were put to death in Luzon were innocent, and I with others discussed this matter with the king, that we might learn what was his will in this grave affair.

From The Philippine Islands, 1493-1898 — Volume 13 of 55 1604-1605 Explorations by Early Navigators, Descriptions of the Islands and Their Peoples, Their History and Records of The Catholic Missions, As Related in Contemporaneous Books and Manuscripts, Showing the Political, Economic, Commercial and Religious Conditions of Those Islands from Their Earliest Relations with European Nations to the Close of the Nineteenth Century by Emma Helen Blair