The term 'left behind' can be used to describe a variety of situations. It can refer to someone who has PASSED away, been FORGOTTEN, outrun, forsook, gone MISSING, DESERTED, FORSAKEN, or ABANDONED. In each case, the person or thing in question has been left behind by someone or something else. This could be due to death, negligence, or a conscious decision to leave them behind. In any case, the result is the same: the person or thing is no longer present and has been left behind.