Daryl F commented
I suggest a checkbox approach, so it puts a block on any discounts. Example: multiple items on a sale; when the clerk applies an order-level discount, the one(s) the merchant has designated by checking the "no discounts" box at the item level in inventory do not receive any discounts, but the items without the checkbox checked DO receive the discount.
Mickey Kwong commented
With this, allow an item to not be discounted. For example in the state of Massachusetts liquor CANNOT be discounted. With the way clover gives discounts today this causes a lot of inefficiencies, especially in a busy Bar