Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
blabbermouthed is an adjective meaning "unwisely talking too much". It carries 2 recorded senses.
unwisely talking too much
prone to communicate confidential information
Definitions, synonyms and semantic relations for blabbermouthed come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.