You can see the King of Swords as a man with the following qualities or, if the the question concerns a woman, as the male part of her psyche. But I tend to reading the kings as the outward side of a person (job, typical ways of acting, the way the life is led...), no matter whether this person is male or female.
The King of Swords is an intelligent, reasonable, rational, pensive man. He can be very witty and adroit, which makes him a great entertainer. You typically meet him in jobs in which critical distachment, objectivity, and clear, abstract thinking are required. If you are entangled in a complicated (intellectual) problem and can go neither back nor forth, the King of Swords will help you. But he is not unproblematic. He can be undercooled and top-headed; he has great difficulties dealing with emotions - he will even refuse trying to. Also, he inclines towards perfectionism and excessive, inappropriate critisicm. That he often hurts people with his sharp tongue he does not even know.