Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unselfishness is a noun meaning "the quality of not putting yourself first but being willing to give your time or money or effort etc. for others". It carries 2 recorded senses.
the quality of not putting yourself first but being willing to give your time or money or effort etc. for others
“rural people show more devotion and unselfishness than do their urban cousins”
acting generously
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 unselfishness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.