Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
declivitous is an adjective meaning "sloping down rather steeply". It carries one recorded sense.
sloping down rather steeply
Definitions, synonyms and semantic relations for declivitous come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.