What does *usury* mean in the Westminster Larger Catechism Question 142?
The Westminster Larger Catechism (1648) Question 142 lists usury among the sins against the 8th commandment (highlight mine):
Q. 142. What are the sins forbidden in the eighth commandment?
A. The sins forbidden in the eighth commandment, besides the neglect of the duties required, are, theft, robbery, man-stealing, and receiving anything that is stolen; fraudulent dealing, false weights and measures, removing landmarks, injustice and unfaithfulness in contracts between man and man, or in matters of trust; oppression, extortion, usury, bribery, vexatious lawsuits, unjust enclosures and depredation; engrossing commodities to enhance the price; unlawful callings, and all other unjust or sinful ways of taking or withholding from our neighbor what belongs to him, or of enriching ourselves; covetousness; inordinate prizing and affecting worldly goods; distrustful and distracting cares and studies in getting, keeping, and using them; envying at the prosperity of others; as likewise idleness, prodigality, wasteful gaming; and all other ways whereby we do unduly prejudice our own outward estate, and defrauding ourselves of the due use and comfort of that estate which God hath given us.
Usury was a bit of a hot topic at the time; Scholastic teaching forbade charging any interest, while some of the reformers (notably Calvin) and others were beginning to draw a difference between permissible and sinful usury (permissible generally being with low rates in cases where it was non-exploitive, sinful being with high rates or to the poor). There was a fair amount of ongoing debate on the subject, however, both internal to Protestant groups and with the Catholic church.
The word "interest" began to be used in the 1520's in Britain to distinguish permissible usury (etymonline) but "usury" was still used to cover both – the 1660 Act for restraining the takeing of Excessive Usury uses both words with no perceptible transition to using usury only for excessive rates.
With this historical and linguistic background, how did the Westminster divines intend "usury" in the 1648 Larger Catechism to be interpreted? Are there any contemporary writings by the divines that would shed light whether they viewed all forms of interest charged as "unjust or sinful ways of taking or withholding" or if they considered some permissible for Christians?
A very related question – is there any later Reformed scholarship addressing this use? I was unable to find much of anything on the topic.