Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
abstruseness is a noun meaning "the quality of being unclear or abstruse and hard to understand". It carries 2 recorded senses.
the quality of being unclear or abstruse and hard to understand
wisdom that is recondite and abstruse and profound
“the anthropologist was impressed by the reconditeness of the native proverbs”
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 abstruseness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.