Suffix -ity Used to form a noun from an adjective; especially, to form the noun referring to the state, property, or quality of conforming to the adjective's description. Used to form other nouns, especially abstract nouns. Many nouns formed with -ity are uncountable; those that are countable form their plurals in -ities.
King Duncan is a fictional character in Shakespeare's Macbeth. He is the father of two youthful sons (Malcolm and Donalbain), and the victim of a well-plotted regicide in a power grab by his trusted captain Macbeth.
Both before and after the regicide, it is Duncan's particularly virtuous nature that enhances Macbeth's sense of guilt. The historic Duncan, incidentally, was a young man when he was betrayed by his general Macbeth.