His lord wel coude he plesen subtilly, To yeve and lene him of his owne good, And have a thank, and yet a cote and hood. (General Prologue 610 – 612)
The Reeve uses trickery to gain not only money, but gratitude. This last makes the Reeve's action particularly heinous because it's not only that he's stealing from his Lord; he's also making him look like an idiot.
Nowher so bisy a man ther nas; And yet he semed bisier than he was. (General Prologue 321 – 322)
There's an awful lot of "seeming" going on in the Man of Law's portrait, which makes us think that, despite the generally neutral tone of it, there might be something going on underneath the surface here.
Or elles he moot telle his tale untrewe, Or feyne thing, or finde wordes newe. (General Prologue 735 – 736)
Here Chaucer says that failing to repeat words as exactly as one heard them is close to lying. Later, in his prologue to the Tale of Melibee, he reverses this position, so it's impossible to say what Chaucer the character really thinks. As for the poet, he has no problem with embellishing and changing often-told tales to suit his purpose.
And thus, with feyned flaterye and japes, He made the person and the peple his apes. (General Prologue 705 – 706)
"Japes" are tricks, and here the word is probably referring to the false relics the pardoner passes off as genuine. One person who won't stand for being made an "ape" is the Host, who calls the Pardoner's relics the garbage that they are.
This worthy man ful wel his wit bisette: Ther wiste no wight that he was in dette. (General Prologue 279 – 280)
Like the Prioress, the Merchant is working really hard to appear to be something he's not: financially solvent. In his case, though, this deception is probably necessary for his business success, whereas for the Prioress it's actually contrary to the obligations of her profession.
[The Prioress] peyned hire to countrefete chere Of court, and to been estatlich of manere, And to ben holden digne of reverence. (General Prologue 139 – 141)
With the Prioress we have the first of many characters who are pretending to be something they're not. The idea of counterfeiting is a word that also appears when Chaucer talks about his repetition of other pilgrim's words. This shows the way the word can have both negative ("faking") and positive ("repeating") connotations.
Wel coude he stelen corn, and tollen thryes. (General Prologue 562)
The Miller cheats his customers by replacing part of the flour they've purchased with worthless filler, or by charging them three times the going price for wheat. This former method of cheating customers foreshadows the one that occurs in the Reeve's tale.
The Reeve's Prologue
Four gleedes han we whiche I shal devyse – Avauntyng, liyng, anger, coveitise; Thise foure sparkles longen unto eelde. (Reeve's Prologue 29 – 31)
The Reeve describes his four powers of the elderly as "gleedes," or coals, and "sparkles," or sparks. By using fire imagery here, he tries to return the spark of vitality to the elderly, so to speak.
The Summoner's Prologue
I yowbisekethat, of youre curteisye, Synyehanherd this falsefrerelye, As suffreth me I may my tale telle. (Summoner's Prologue 5 – 7)
The Summoner believes that the opportunity to tell his tale is the appropriate response to lies. As Chaucer has done in the General Prologue, then, he links tale-telling and lying.
The Merchant's Epilogue
Lo, whiche sleightes and subtilitees In wommen been! for ay as bisy as bees Been they, us sely men for to deceyve, And from the soothe evere wol they weyve. (Merchant's Epilogue 1209 – 1212)
Of the powers the Reeve attributes to the elderly, the one they share with women is deceit. The other thing these two groups have in common is that they have less power in medieval society.
Discreet he was and of greet reverence: He semed swich, his wordes weren so wyse.
"Seeming" is not a good thing in The Canterbury Tales. The appearance of this word usually marks some kind of deception that's going on, someone trying to appear to be something they're not.