A young analytically inclined person. A vibrant mind with a strong need for communication. A salesman.
If this card represents an actual person, he's one of those who brings complete chaos then leaves all the mess for you to tidy up. Quite often it indicates a period of increased activity that doesn't lead to anything substantial unless other cards say otherwise. I've found that the Prince of Swords normally indicates three to four weeks of life being hectic (but that applies from the last time you see the card in the reading) although I've known some people who seem to live under the permanent influence of this energy. People will be coming and going, and you need to stay flexible.
Air signs. Gemini, Libra, and Aquarius. Crowley gives from 21' Capricorn to 20' Aquarius.
Examples With Other Cards
Court cards will often act as a kind of channel for other cards and in this case, if the Prince of Swords shows up with other sword cards he will magnify the energy of the card concerned. This card is supposed to be about temporary disruption, but if other more stable cards show up in the reading then whatever chaos or upset occurs, it's an even stronger reference to a passing storm. The Hierophant, the Ten of Discs, and The Empress, are good indicators of stability that can withstand the chaos of Prince of Swords.
Prince and Knight are used interchangeably.