How to define a defect?
Defect of a commodity is that which diminishes its value in a way that causes harm to the buyer and this is usually defined to the public as a defect a person would return an item for.
The Ruling of a Defective Commodity
If the defect exists prior to contracting and the buyer only happens to know about it after the sale is concluded, he has the choice of the following three options In Shaa Allah:
Option 1: To retain the commodity and receive a compensation for the defect, which is estimated according to the supposed price of the commodity if free of defect and its price in case of defect.
Option 2. The buyer may return the commodity to the seller and take his money back.
Option 3. The buyer may continue to keep the commodity and not request anything back from the seller.
[Originally from the website Alifta.net along with additional note]
AbdulFattaah Bin Uthman