adj.
1) ~ to + inf. (it was ~ of him to blurt that out)
2) ~ that + clause (it is ~ that she was left out)
INEXCUSABLE
Meaning of INEXCUSABLE in English
The Bbi combinatory dictionary of English, a guide to word combinations. Комбинаторный словарь английского языка Bbi. Руководство по словосочетаниям. 2012