The affix vuñ comes after the word nagara in the remaining senses, when censure or praise is implied.,
The word कुत्सनं which is equivalent to निन्दनं or 'blame or censure'; and प्रावीण्यं which means नैपुण्य \dexterity\, qualify the sense of the affix. Thus नागरकः, 'a knave, a cunning person, or a skillful person'. The word literally means 'a town-born, or town-bred', but by the usage of language, it always denotes a person having the vices or virtues of a town, such as a thief or an artist.
Why do we say \when censure or dexterity is implied\? Observe नागराः ब्राह्मणाः 'the Nagara Brahmanas\.,