Indirect characterization is a technique an author uses to provide a sense of character through speech, clothing, or actions. Direct characterization involves what the narrator says about the character; in Chaucer's case, everyone seems to be described positively—as "worthy"—due to the narrator's naivete.
One of the pleasures of the text Chaucer provides in the General Prologue involves detecting the irony between what is said about these pilgrims and what indirect characterization suggests is more accurate.
For instance, the Knight is praised highly and seems to be a man committed to virtuous life:
That fro the tyme that he first bigan
To riden out, he loved chivalrie,
Trouthe and honóur, fredom and curteisie.
If one accepts Terry Jones's claim in his book Chaucer's Knight, this is a battle-scarred knight whose ideals of chivalry have led him into a series of the medieval world's bloodiest crusades, as is indicated by the series of places in which he has won his knightly success. While he may have initially been committed to the idealized chivalric values, he returns a man with PTSD, perhaps traumatized enough to be in a state of near shock:
And of his port as meeke as is a mayde.
He nevere yet no vileynye ne sayde ...
Similarly, the Monk does not seem particularly villainous, but he does seem to be out of place in the feudal world. While a clergyman should be devoted to prayer, this man would be better suited to a life in the second estate (those who fight):
He yaf nat of that text a pulled hen
That seith that hunters ben nat hooly men,
Ne that a monk, whan he is recchelees,
Is likned til a fissh that is waterlees,—
This is to seyn, a monk out of his cloystre.
But thilke text heeld he nat worth an oystre ...
It seems that this man is forced into living the monastic life, and he risks his salvation in being more willing to live a different lifestyle and violate his oaths.
Both the Franklin and the Wife are described in terms of the indulgences they enjoy. The Franklin, for instance,
Wel loved he by the morwe a sop in wyn;
To lyven in delit was evere his wone,
For he was Epicurus owene sone,
That heeld opinioun that pleyn delit
Was verraily felicitee parfit.
Similarly, the Wife is noted for her excess and her indulgences:
Hir coverchiefs ful fyne weren of ground;
I dorste swere they weyeden ten pound
That on a Sonday weren upon hir heed.
Hir hosen weren of fyn scarlet reed,
Ful streite y-teyd, and shoes ful moyste and newe.
Boold was hir face, and fair, and reed of hewe.
She was a worthy womman al hir lyve;
Housbondes at chirche dore she hadde fyve,
Withouten oother compaignye in youthe ...
These are just a few of the small brushstrokes Chaucer provides to characterize these figures. Close examination of their full portraits reveals additional qualities that enrich our sense of personality, as does a close reading of their individual tales as expressions of their world view and of the interests that motivate their choices in tale and in life.