well: in a good, right, or fitting way
This is the adverb of the common word for "good, fine, noble." Its basic sense is simply "well": doing something in a good, right, or fitting way. Most of its uses fall into two broad groups: carrying out an action well or admirably (managing a household well, building well, running well), and saying or seeing something rightly or correctly (Isaiah prophesied rightly; "well said, teacher").
Beyond that plain core the word settles into a handful of set phrases. Paired with "do," it can mean to act rightly or to perform a good deed, and in a letter it becomes a courteous way of thanking or approving someone ("you did well to come," "you will do well to send them on their way"). To "do well to" people means to treat them kindly, and to "speak well of" someone means to praise.
Like the English "well," it can also be turned to irony. When Jesus tells his critics they have a fine way of setting aside God's command, the word's usual approval is flipped into a rebuke. Once it even marks a place rather than an action, as when a rich visitor is told to sit in a good seat.