Virtuousness comes from 'virtuous' + '-ness'. 'Virtuous' is from Latin 'virtus' ('excellence, moral worth'), from 'vir' ('man'). In current use it is a noun meaning "the quality of being morally good or upright". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The historical chain includes Latin virtus and Latin vir. Related English forms include virtuous, virtue, and virtuoso. The word's history is thus visible in its construction: the components remain interpretable even after the whole expression has settled into a conventional English meaning.