Final answer:
The negotiation tactic of pointing out an undesirable product characteristic to drive the price down is known as the ding tactic.
Step-by-step explanation:
When you negotiate with a supplier and attempt to drive down the price by pointing out an undesirable characteristic of their product, you are using what is known as the ding tactic. This negotiation strategy involves highlighting a flaw or defect in the product to justify a lower price. It is a way of playing hardball in the negotiation process, aiming to tilt the balance of the discussions in your favor by putting the supplier on the defensive.