This is not me being pedantic, I think it's just become a term in the world of PSR and FFP, but that would be just "profit"
"pure profit" is a term reserved for the selling of an academy player. This part I'm not sure about, but the "pure profit" deals may also sidestep the amortization process. IE, if you sell a purchased player, the income is spread over the 5 years or payment plan, but if you sell an academy product, it all goes in on Y1. Like I say though, I'm not 100% sure on that part.
Speaking of all that, looks like we might start getting linked to Gallagher again soon