Definition of "unutterably"

We both of us went on our knees, and, feeling unutterably sad, a whispered prayer went up from our lips as the poor fellow's soul flitted away to a happier and brighter world, and all was over.

1887, Harriet W. Daly, Digging, Squatting, and Pioneering Life in the Northern Territory of South Australia, page 167

The rapid reconquest of the capital, Kabul, by the Taliban after two decades of a staggeringly expensive, bloody effort to establish a secular government with functioning security forces in Afghanistan is, above all, unutterably tragic.

2021 August 15, “The Tragedy of Afghanistan”, in The New York Times‎