Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
contemptuousness is a noun meaning "the manifestation of scorn and contempt". It carries one recorded sense.
the manifestation of scorn and contempt
“every subordinate sensed his contemptuousness and hated him in return”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for contemptuousness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.