Self-confidence is a closely related socio-psychological concept related to self-esteem. It can manifest itself in a number of ways, some deemed positive, others negative. The term's first recorded usage was in 1653.
To have self-confidence is to have confidence in one's self. Confidence in this regard is a state of certainty, arrogant or otherwise. The phrase doesn't necessarily equate to a belief in in an ability to do all things, but rather, an assurance that someone is capable and and comfortable with herself.
A natural extension of self-confidence is self-esteem, a word which means that the holder has a realistic respect for and favorable impression of herself. Generally speaking, most agree that a possessing self-esteem is ideal. However, self-confidence is the more boisterous of the two terms, and when used, can very often refer to another, less ideal variation.
Self-confidence can often refer to a confidence in one's self, thought excessive, inflated or otherwise unwarranted. This is hubris and is the mirror image of conceit or arrogance. In fact, the Oxford English Dictionary defines self-confidence as "confidence in oneself; often in an unfavourable sense, arrogant or impudent reliance on one's own powers."
Hubris is defined in the Oxford English Dictionary as "presumption, originating towards the gods; pride, excessive self-confidence." Here, excessive self-confidence is equated with the belief that one thinks they are god-like in some way. Needless to say, such showings of confidence are often ridiculed or otherwise frowned upon.
At the opposite end is a total lack of self-confidence, also deemed to be detrimental. Shyness and a fear of failure are the most common signs of lacking self-confidence, but it can be manifested in other ways as well.
