Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
addlebrained is an adjective meaning "stupid and confused". It carries one recorded sense.
stupid and confused
“blathering like the addlepated nincompoop that you are”
“a confused puddingheaded, muddleheaded fellow”
Definitions, synonyms and semantic relations for addlebrained come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.