Knight of Swords
Upright
Skill, bravery, capacity, defence, address, enmity, wrath, war, destruction, opposition, resistance, ruin. There is therefore a sense in which the card signifies death, but it carries this meaning only in its proximity to other cards of fatality.
Reversed
Imprudence, incapacity, extravagance.
A. E. Waite, The Pictorial Key to the Tarot (1911), Part III §2The picture
He is riding in full course, as if scattering his enemies. In the design he is really a prototypical hero of romantic chivalry. He might almost be Galahad, whose sword is swift and sure because he is clean of heart.
Older readings
A soldier, man of arms, satellite, stipendiary; heroic action predicted for soldier. Reversed: Dispute with an imbecile person; for a woman, struggle with a rival, who will be conquered.
A. E. Waite, The Pictorial Key to the Tarot (1911), Part III §4. Waite collected these and says they often disagree with the main meanings.Waite wrote in 1911 and some of his meanings show it. Tarot is a tradition of reflection, not a prediction, and no card decides anything for you.