1. I think the sentence should read "with a kind of cold reserve...". It means with a quiet control, controlling his emotions, with little expression of emotion. 2. "back order" means that your company has an order for a product but cannot fulfill the order because you are out of inventory. The product is in back order until you receive new inventory that you can ship out.

In this context cold reserve means that he was holding back what he really wanted to say and he was not displaying warm or friendly body language. He was not feeling or acting warmly toward the person. Back order is the status an order is categorized in when an item is out of stock and is being ordered from the wholesaler or is in production. Nice questions! I hope the answers help you understand.

There are two things that are wrong with this sentence: 1. It will have to be "...with the kind of cold reserve that ..." for it to be grammatically correct. 2. "Cold reserve" may "melt" but does not "explode". "Cold reserve" signifies lack of warmth. Where did you see this sentence?