Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
perceptiveness is a noun meaning "a feeling of understanding". It carries 4 recorded senses.
a feeling of understanding
delicate discrimination (especially of aesthetic values)
“arrogance and lack of taste contributed to his rapid success”
“to ask at that particular time was the ultimate in bad taste”
perception of that which is obscure
the quality of insight and sympathetic understanding
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 perceptiveness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.