Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
overpoweringly is an adverb meaning "incapable of being resisted". It carries one recorded sense.
incapable of being resisted
“the candy looked overwhelmingly desirable to the dieting man”
Definitions, synonyms and semantic relations for overpoweringly come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.