Full Idea
A virtue can be defined as 'a deep and enduring acquired excellence of a person, involving a characteristic motivation to produce a certain desired end and reliable success in bringing about that end'.
Gist of Idea
Virtues are deep acquired excellences of persons, which successfully attain desire ends
Source
Linda Trinkaus Zagzebski (Virtues of the Mind [1996], II 2.7)
Book Reference
Zagzebski,Linda: 'Virtues of the Mind' [CUP 1996], p.137
A Reaction
She puts this in bold, and it is the culminating definition of a long discussion. It rather obviously fails to say anything about the nature of the end that is desired. Learning the telephone book off by heart seems to fit the definition.