Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
ineffably is an adverb meaning "to an inexpressible degree". It carries one recorded sense.
to an inexpressible degree
“she was looking very young tonight, and, as usual, indescribably beautiful, in a simple strapless dress of a green and white silky cotton”
Definitions, synonyms and semantic relations for ineffably come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.