lamentably
adverb
UK/ləˈmen.tə.bli/
US/ləˈmen.t̬ə.bli/
Definitions of lamentably adverb
in a regrettable or disappointing manner; of very poor quality or performance.
The movie was lamentably produced, making it a disappointment.
His performance was lamentably below expectations.
We found, lamentably, that they were not capable of completing the project.