Syllable division and stress derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
imperativeness is a noun meaning "the state of demanding notice or attention". It carries 2 recorded senses.
the state of demanding notice or attention
“the insistence of their hunger”
“the press of business matters”
the quality of being insistent
“he pressed his demand with considerable instancy”
archaism
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 imperativeness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.