Translation guide
Describes something that is defective, not working correctly, or has a flaw. Covers physical objects, reasoning, and systems.
The most common meaning: a product, device, or part that has a defect and does not function as intended.
Standard way to say a machine or device is broken/out of order. Emphasizes the state of not working.
Describes an argument, logic, or reasoning that is unsound or contains errors.
Directly modifies nouns like 論理 (logic) or 推論 (reasoning).
Describes memory or senses that are unreliable or inaccurate.
Literally 'memory is vague'; natural way to say memory is faulty/unreliable.
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.
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.
That's faulty logic.
Means 'mistaken/erroneous'. Common for incorrect reasoning.
His argument is based on a faulty premise.
Means 'illogical/incoherent'. Emphasizes lack of logical flow.
The explanation was faulty.
My memory of that day is faulty.
Means 'memory is uncertain/unreliable'. Slightly more formal.
The witness's memory was faulty.