For me, a person who hits a stray dog with a stone just for fun is a bad person. One who gives pains to friends for no reason is a bad person. One who looks at wrong things, and decides to do nothing is evil. One who hurts feelings of loved ones is a bad person. One who lets other people sleep in hunger without doing anything about them is a bad person. One who wants bigger share of the pie is a bad person. One who shouts and makes others fear him/her is a bad person. One who never tries to understand feelings of others is a bad person. One who treats poor people as dirt, is a bad person. One who decides about characters by looks and passes judgments is a bad person. One who reads a sad story in the newspaper, without getting affected in any way is a bad person. One who shows no respect for those who work for others is a bad person. One who does not sympathize at others losses is a bad person. One who always tries to prove his/her superiority over others is a bad person. On and on I can write. What is not good is bad. That is how I call such people bad. Rather than calling them as not good persons, I call them as bad persons. All this may look quite shocking and many will protest about what all I have written above. All right, let me say, that I will not call the person a bad person, but the act as a bad act. I hope that now I am more acceptable.
Then, what is evil? Evilness is a quality in a person, whereby that person hurts others in ways that the very life is taken away. One need not kill with a sword to be called evil. At times, making false allegations on someone who never did what he/she is being blamed with is enough to kill the spirit and the body. That act is evil, and the person who acts like that is evil.