Inferiority complex is a term used to describe people who compensate for feelings of inferiority (feeling like they're less than other people, not as good as others, worthless, etc.) by acting in ways that make them appear superior. They do this because controlling others may help them feel less personally inadequate.
According to Alfred Adler, a feeling of inferiority may be brought about by upbringing as a child (for example, being compared to a sibling), physical and mental limitations, or experiences of social discrimination (for example, having limited opportunities due to race, economic situation, or gender).
On the other hand, some people with this disorder are simply timid and frequently feel less than.
An inferiority complex may cause an individual to overcompensate for their perceived weaknesses. For example, someone who feels inferior because they are shorter than average may become overly concerned with their appearance - they may go on a strict diet or engage in rigorous exercise, hoping that a slimmer body will make them appear taller. If this is taken to the extreme, it becomes a neurosis.