Above, the dictionary version of "to bully" is laid out very neatly.   It does not; however, tell of the hurt, the fear, the self-diminishing trauma that can occur to the victim of the bully.  
In the past, bullies were a way of life, a rite of passage to those in school.  The victims were not protected but told to "toughen up", to "get a thicker skin", or to "shake off" the attacks.  The damage done by these acts, whether verbal or physical, were not noted, not researched.  
Today, we have more information available to us.  More studies being put out on the internet of the damage that can occur from bullies and information, as well, about who bullies usually are.  Unfortunately, we also have more hurtful, more permanent forms of bullying due to social media and sites, such as YouTube.  

And because of this instantly invasive and wide-spreading form of bullying, the instances of suicide due to bullying have also risen by leaps and bounds


 "Hurt people, hurt people",

is a quote by Will Bowen, author of Complaint Free Relationships, Transforming Your Life One Relationship At a Time.  With increasing research in the field of relationships and mental health, this has been proven time and again.  Bullies are usually very hurt people.  

Now, of course, this does not make it alright for bullies to act upon others, nor does it make it easier to accept the actions, but should those in our school systems, or other adults note this phrase when dealing with the subject of bullying, perhaps we can stop the victim from being hurt and start to heal the bully.  Understanding, compassion, and nurturing to these children who act upon another child could be a start of eradicating the bully from our culture in the future.