Leadership is the ability of an individual or a group of people to influence  and guide  followers or members  of an organization , society or team. Leadership is the capacity to set and achieve challenging goals , take fast and decisive actions when needed. 

Overall we can say that leadership is the set of characteristics that makes a good leader.  

Moreover, a leader must have some qualities like honesty,  knowledge,  consistency, visionary outlook, courage, willpower, efficient communication skill , prompt decision making skill etc.