Charisma means an innate ability to "influence" people and be impressionable by your mere presence.
When it is stated that someone has a charismatic personality it means that they can move people be impressionable just by being in their company. The word originated from the Greek word Kharisma which means 'gift' or 'divine favor'. It refers to an individual's innate ability with persuasiveness and is supposed to be a natural gift which allows them to powerful and seductive.