The King of Swords (King of Wind in the Penguin tarot deck) is a court card that represents logic, the expectation of the truth, giving out the truth, clear thinking, direct communication, and intellectual authority. This is the card of someone who is courageous enough to go after desires and wants. Emotions are kept in check as well while learning about certain truths that may be unpleasant.
The King of Swords has a detached trait as well and there may be a concern about not being emotional in any way while having to deliver unpleasant or difficult truths. However, this is when it is important to remain detached. This card encourages you to always use logic and common sense whenever it comes to making plans and navigating any type of path. It is important to stay in the loop with anything that involves you so that you are properly informed of anything that you must know.
When the King of Swords shows up in reverse it can represent the abuse of power or manipulation. It can also represent being too quiet even with being in a powerful position as well as withholding the truth.
Astrologically, Capricorn and Aquarius are linked to this card.