||1) It's an English term, and it's not part of our laws. There are concepts in Jewish Law that are somewhat similar, however.
2) Anything done within the rules of the Torah, is OK to do. The Halachah will usually tell you when & where there is a reason to be stricter. Selling Chometz is very complicated and very often not done properly, causing the owners to commit a sin of a serious magnitude. The same person won't be caught dead drinking Coca-Cola that has corn syrup as an ingredient on Pesach. Go figure!