Translation guide
Describes something that is defective, not working correctly, or has a flaw. Covers physical objects, reasoning, and systems.
This washing machine is faulty.
A defective product; used as a noun. Common in consumer contexts.
It was faulty, so I returned it.
More formal; 'has a defect/flaw'. Used for products, designs, or systems.
This car is faulty.
Common in technical/business contexts; 'has a malfunction/glitch'. Softer than 欠陥.
The software is faulty.
Describes an argument, logic, or reasoning that is unsound or contains errors.
Describes memory or senses that are unreliable or inaccurate.
The English word 'faulty' covers many nuances. Do not use a single Japanese word for all cases. Choose based on context: physical defects vs. abstract flaws.
His argument is based on a faulty premise.
The explanation was faulty.
The witness's memory was faulty.