Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
boniness is a noun meaning "extreme leanness (usually caused by starvation or disease)". It carries one recorded sense.
extreme leanness (usually caused by starvation or disease)
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 boniness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.