(Note: this is a collection of the meanings attributed to the cards by some occultists in the past centuries. It does not reflect my own study or opinion of the cards. It is only meant as a quick comparative reference as I develop my own take.)

Paul Foster Case (and Ann Davies)

The time period is from the beginning of the last decanate of Gemini to the second decanate of Cancer, June 11 to July 12, combining the rulers hips of Saturn and Uranus, the Moon and Mars.
Well Dignified: a man subtle and secretive, crafty, psychic, artistic; of strong, violent desires but calm exterior. He is friendly to the Querent and really wise. Ill Dignified: evil and merciless and likely to be attracted by occult studies promising power or knowledge for the satisfaction of desire and control of others; without purification of character. Usually fair-haired with blue eyes.
(From the Oracle of Tarot course)

A. E. Waite

He holds a short sceptre in his left hand and a great cup in his right; his throne is set upon the sea; on one side a ship is riding and on the other a dolphin is leaping. The implicit is that the Sign of the Cup naturally refers to water, which appears in all the court cards. Divinatory Meanings: Fair man, man of business, law, or divinity; responsible, disposed to oblige the Querent; also equity, art and science, including those who profess science, law and art; creative intelligence. Reversed: Dishonest, double-dealing man; roguery, exaction, injustice, vice, scandal, pillage, considerable loss.
(From The Pictorial Key to the Tarot)

Aleister Crowley

(Note: Crowley and the Golden Dawn swap around King and Knight. This is in part true of Waite as well.)
The Knight of Cups represents the fiery part of Water, the swift passionate attack of rain and springs; more intimately, Water’s power of solution. He rules the Heavens from the 21st degree of Aquarius to the 20th degree of Pisces. He is clothed in black armour furnished with bright wings which, together with the leaping attitude of his white charger, indicates that he represents the most active aspect of Water. In his right hand he bears a cup from which issues a crab, the cardinal sign of Water, for aggressiveness. His totem is the peacock, for one of the stigmata of water in its most active form is brilliance. There is here also some reference to the phenomena of fluorescence.

The characteristics of the person signified by this card are nevertheless mostly passive, in accordance with the Zodiacal attribution. He is graceful, dilettante, with the qualities of Venus, or a weak Jupiter. He is amiable in a passive way. He is quick to respond to attraction, and easily becomes enthusiastic under such stimulus; but he is not very enduring. He is exceedingly sensitive to external influence, but with no material depth in his character.

When the card is ill dignified, he is sensual, idle and untruthful. Yet with all this he possesses an innocence and purity which are the essence of his nature. But he is, on the whole, so superficial that it is hard to reach this depth. “His name is writ in water.”

In the Yi King, the fiery part of Water is represented by the 54th Hexagram, Kwei Mei. The commentary is singularly obscure, and somewhat sinister. It deals with the difficulties of rightly mating such opposites as fire and water (compare the Queen of Wands; but in that case Water is the calming and modulating influence, while here it is Fire which creates trouble.) Swiftness and violence ill suit a character naturally placid; it is rare indeed to meet with a person who has succeeded in harmonizing these conflicting elements. He tends to mismanage all his affairs; and unless sheer good fortune attend him, his whole career will be an unbroken record of failure and disaster. Often his mental “civil war” ends in schizophrenia or melancholy madness. The abuse of stimulants and narcotics may precipitate the catastrophe.
(from The Book of Thoth)

Golden Dawn’s Book T

A BEAUTIFUL, winged, youthful Warrior with flying hair, riding upon a white horse, which latter is not winged. His general equipment is similar to that of the Knight of Wands, but upon his helmet, cuirass and buskins is a peacock with opened wings. He holds a cup in his hand, bearing the sigil of the scale. Beneath his horse’s feet is the sea. From the cup issues a crab. Graceful, poetic, Venusian, indolent, but enthusiastic if roused. Ill dignified, he is sensual, idle and untruthful.
He rules the heavens from above 20 Degree of Aquarius to 20 Degree of Pisces, thus including the greater part of Pegasus.
(from Book T)

Etteilla

Blond man
Upright. This card, as far as the medicine of the spirit is concerned, means, in its natural position: Blond Man, Honest Man, Probity, Equity, Art, Science.
Reversed. Man occupying a good position, Distinguished man, Honest man. – Dishonest man. – Exaction, Concussion, Injustice, Brigand, Thief, Dissimulator. – Vice, Corruption, Scandal.

MQS