Absence of malice means that somebody didn't do something bad on purpose. A simple example to explain absence of malice to someone who is 5 would be if a younger brother has candy in his pocket, and his older brother accidentally knocks it on the floor and all of it spills out. The older brother didn't mean to do it, so even though candy was spilt, the older brother didn't do it on purpose, so there was no 'malice' in it, only an accident.