I continue to be with people who ask the definition of competency. It is important to get this firmly in mind before getting deeper into the specific competencies that are critical to exceptional leadership.

Here is a definition from the Society for Human Resources Management (SHRM) that I like -

"Leadership competencies are leadership skills and behaviors that contribute to superior performance.

By using a competency-based approach to leadership, organizations can better identify and develop their next generation of leaders.

Essential leadership competencies and global competencies have been defined by researchers."

http://www.shrm.org/hrdisciplines/orgempdev/Pages/competencies.aspx