Meanings according to Rider-Waite:
ASTROLOGICAL SIGNIFICANCE: Mercury in Gemini as a symbol of dexterity, wit, cunning, and resourcefulness.
KING OF SWORDS The King of Swords is the masculine manifestation of the element of air. This is the power of a sharp, swift, subtle mind, expressing itself here both in its creative, multifaceted, and often unpredictable form, and in the form of cunning and ironic audacity. Such a mind is an excellent instrument for cognition, comprehension, analysis, logical reasoning and abstraction, mathematical and purely practical calculation, the resolution and comprehensive solution of any problems. However, where it dominates over all other faculties, its negative sides also manifest themselves: pure intellectualism, coldness of feelings, caustic and cynical fault-finding, a fondness for wordplay, and an "extraordinary lightness of thought."
From the book: Hajo Banzhaf. THE TAROT HANDBOOK. Translated from German by E. Kolesov. Publisher: Center for Astrological Research, 1999.
KING OF SWORDS A person who expresses his positions or intentions by means of the Sword. His personal qualities, however, are determined by the qualities of the Wand. To those around him he appears clear and direct, perhaps single-minded. To achieve his goal, he breaks resistance, gets to the root of things, and without hesitation cuts off everything that seems to him superfluous. For this reason, many people respect him rather than love him, and some even fear him. If the companion of the KING OF SWORDS shares his professional interests, he will make her his partner. But he will part with his beloved without hesitation if their relationship interferes with his career or other interests. Therefore, if your friend is a KING OF SWORDS, try to be careful!
Upright position Astrological equivalents: Aries, Libra, Mars in Libra, the First House. A strong and energetic person, though at times excessively harsh and straightforward, the KING OF SWORDS relies more on himself than on others. Physically stronger than most of the people around him, he nevertheless is perfectly aware of the limits of his capabilities. Often the KING OF SWORDS represents a personality of heroic cast. We can find many people corresponding to the spirit of this card among leaders who assert their power through openly forceful methods. Moreover, the "spectrum" of this card is extraordinarily wide: from a criminal kingpin to a military commander of the Chapayev type. Very often whole epics of rumors, gossip, and myths are composed around the personality of the KING OF SWORDS — and indeed he himself constantly provides occasions for this. Since the KING OF SWORDS works with dense matters, both he and his deeds, as a rule, are visible and comprehensible to the people around him. The KING OF SWORDS may also act as a peacemaker. However, even here he will act from a position of strength. He is the embodiment of the third force, balancing the other two opposing ones.
Reversed position Astrological equivalents: Aries, Libra, Mars in Aries, Mars in Cancer. If in the upright position the KING OF SWORDS showed us an energetic and circumspect person, clearly aware of his own capabilities, then in the reversed position the KING OF SWORDS is either utterly devoid of this quality, or, on the contrary, overly cautious and fearful. In the first case we have a reckless slasher ("no need to think, just leap"), in the second: "What if something happens to me because of this?" But in any position the KING OF SWORDS indicates a very passionate person. Incidentally, this quality is characteristic of all "sword-bearing" court cards.
If the card signifies an action: A. Upright card As it were, the foundation is being laid for a future action or process. At this stage the final decision is made and the "scope of work" is determined. Everything is very concrete. The time of worries and hesitations has passed; the time has come to act.
B. Reversed position The time to act has not yet come, since there is no concrete formulation of the task. Everything is very global and vague.