Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
diabolic is an adjective meaning "showing the cunning or ingenuity or wickedness typical of a devil". It carries 2 recorded senses.
showing the cunning or ingenuity or wickedness typical of a devil
“devilish schemes”
“the cold calculation and diabolic art of some statesmen”
“the diabolical expression on his face”
“a mephistophelian glint in his eye”
extremely evil or cruel; expressive of cruelty or befitting hell
“something demonic in him--something that could be cruel”
“fires lit up a diabolic scene”
“diabolical sorcerers under the influence of devils”
“a fiendish despot”
“hellish torture”
“infernal instruments of war”
“satanic cruelty”
“unholy grimaces”
Definitions, synonyms and semantic relations for diabolic come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.