There is a fine line between the psychopath vs sociopath. In fact, their disorders are so similar that the Diagnostic and Statistics Manual of Mental Disorders lumps these two groups into one disorder: Dissocial Personality Disorder. However, there are clear differences between psychopaths and sociopaths which we'll outline here.
A similar characteristic of both psychopaths and sociopaths is a lack of remorse for one's deeds. Both groups have some type of aggressive or manipulative behavior whether it's immediately visible or not. Psychopaths and sociopaths often instill guilt and use pity as a weapon against those who disapprove of their actions.
There are many differences between psychopaths and sociopaths. A sociopath typically does what he feels like doing even if it hurts people. There is no remorse for misbehavior or fear of negative consequences. Some sociopaths are visibly hostile, and some just have no sense of empathy. A lack of empathy means that the sociopath finds it impossible to put himself in other people's shoes.
A psychopath often shows manipulative and antisocial behavior along with a high sense of arrogance. Some psychopaths are violent and some are not. The psychopath is typically not psychotic and has as good a sense of right and wrong as most other people. He will manipulate people knowing that his behavior is not approved of by peers. The psychopath has a remarkable ability to ignore the conscience.
Psychopaths tend to appear normal and socially adjusted compared to sociopaths who are often more alienated. Social interaction is a staple of psychopathy. Otherwise, the psychopath would be bored with no one to manipulate. When the psychopath stirs up trouble and gets called out on it, he will either conjure up pity, blame someone else for the action or outright deny it and make the accuser feel guilty. The arrogance of the psychopath makes it easy to project the "bad guy" archetype onto innocent people who disapprove of the psychopath's actions.
The psychopath vs sociopath discussion is a very confusing topic in the world of psychology. One article cannot help you diagnose your psychopathic or sociopathic neighbor. The tests that are used to make diagnoses are very long. If you suspect one of these disorders, you'll just need to find some way to get the person to take the tests. Good luck if this person is a psychopath, however. People with this disorder do not have any motivation toward self improvement.