Customers who have spent more than the average on the store products but not recently. Either you have lost them already or will lose them soon.
Consider them as Prime Candidates for the win-back campaigns using discount ladders. For example, start with 5% discount ladders, followed by 10% if they didn’t place any order yet. The campaigning goal for this segment is to bring the customers back for another order, even if that order isn’t as large as usual.