What does "card" in the title "Gwydonius; The Card of Fancie" mean?

Question

Robert Greene's novel Gwydonius; The Card of Fancie was first published in 1584. The novel's main character, Gwydonius, is the only son of the the duke of Mettelyne (presumably Mytilene). He travels to Alexandria (it is not clear whether this refers to Alexandria in Egypt or to one of the many other cities with the same name), where he falls in love with Castania, the only daughter of the duke of Alexandria. Castania has another suitor named Valericus, who is of low birth. In addition, in the second half of the story, the duke of Alexandria's son falls in love with the duke of Mettelyne's daughter.

Fancy has several meanings, including the following (quoted from Wiktionary):

1. The imagination.
2. An image or representation of anything formed in the mind; conception; thought; idea.
3. An opinion or notion formed without much reflection; an impression.
4. Love or amorous attachment.

Card also has many meanings, but I don't see which one is meant by the novels title.

Answer 1

Helmut Bonheim argues that ‘card’ means compass:

The title—The Carde of Fancie—followed a pattern which remained popular until the later years of the sixteenth century: it consisted in combining the name of a concrete object with the name of some abstract quality. Greene knew the pattern from such works as Painter’s Palace of Pleasure (entered in the Stationers’ Register in 1562 as The Cytie of Cyvelitie) or from Whetstone’s Rocke of Regarde (1576). Greene’s friend, Henry Chettle, wrote a Forrest of Fancie, which contained “pleasaunt histories … in prose”. In both book titles the word fancie means love or infatuation, and the carde is the mariner’s card or compass, which swings and swivels to and fro like man’s affection. The subtitle speaks of those who guide their course “by the compass of Cupid”, as do both Gwydonius and Castania; she eventually resolves: “he shall be the starre shall guide my compasse”.

_{Helmut Bonheim (1978). ‘Robert Greene’s Gwydonius, the Carde of Fancie’. Anglia-Zeitschrift für englische Philologie 96, p. 45.}

This is sense 4a in the OED:

4.a. The circular piece of stiff paper on which the 32 points are marked in the mariner's compass.

_{Entry for card, n.2. Oxford English Dictionary.}

Robert Maslen suggests that ‘card’ is polysemous, but that the primary meaning is chart:

The instability of Gwydonius can be summed up in the changing connotations of the term ‘fancy’ in the romance. The subtitle—The Card of Fancy—suggests it is a verbal chart or map of the affections, although a ‘card’ could also be a compass or a component in a card-game. Fancy in Greene’s work can only be mapped, its course traced like that of a storm-tossed vessel; it can be won with luck, like a game of cards, but it cannot be shaped, directed, or expunged.

_{R. W. Maslen (2013). ‘Robert Greene’. In Andrew Hadfield, ed., The Oxford Handbook of English Prose 1500–1640, Oxford University Press, p. 199.}

This is sense 3a in the OED:

3.a. A map or plan; = chart n.1 Obsolete.

_{Entry for card, n.2. Oxford English Dictionary.}

For this sense, the OED includes the following citation, in which ‘card’ is used metaphorically, perhaps in a similar fashion to Greene’s ‘card of fancy’:

1604   Shakespeare Hamlet v. ii. 107 + 4   Hee is the card or kalender of gentry.

Answer 2

It is almost certainly the sixth of the definitions of card in your link.

(informal) An amusing or entertaining person, often slightly eccentrically so

or as the definition at Wolfram Alpha has it...

A witty amusing person who makes jokes.

Usage of the word in this sense isn't so common nowadays as it was then but it is still understood. It fits your synopsis of the book.