Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
neanderthalian is an adjective meaning "relating to or belonging to or resembling Neanderthal man". It carries one recorded sense.
relating to or belonging to or resembling Neanderthal man
“Neanderthal skull”
Definitions, synonyms and semantic relations for neanderthalian come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.