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