Defective (adjective)

1. Faulty or imperfect in some way; not working properly or according to plan.
2. Having a physical or mental condition that limits normal activity or development.

Origin:

The word "defective" is derived from the latin word "defectus" which means "failure" or "deficiency". it has been used in english since the late 16th century.

Examples:

1. The product was defective and had to be returned to the manufacturer.
2. The machine was found to be defective and needed to be repaired.
3. The defective item was replaced under warranty.
4. The defective part was identified as the cause of the problem.
5. The defective gene causes the disease.