Wiktionary
disappointingly
adv. In a disappointing manner
WordNet
disappointingly
adv. in a disappointing manner; "the discoverer of argon, Sir William Ramsay, looked disappointingly ordinary"
Usage examples of "disappointingly".
The man in knickers, hired probably because he resembled the archetypal Irish immigrant--craggy, handsome, thick reddish hair, square face crosshatched with weathered lines--was holding forth in disappointingly American tones.
Fridolin and Albertina were glad to have escaped from a disappointingly commonplace masquerade prank, and soon sat like two lovers, among the other couples, in the buffet, eating oysters and drinking champagne.