Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
disappointedly is an adverb meaning "in disappointment; in a disappointed manner". It carries one recorded sense.
in disappointment; in a disappointed manner
“she left the gambling table disappointedly”
Definitions, synonyms and semantic relations for disappointedly come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.