A flaw is a problem or error (small or large) that makes something less effective or
valuable. The word flaw can be used for problems in objects, ideas, or people’s
character:
▶️ Objects: This diamond is less expensive because it contains several flaws.
▶️ Ideas: There’s a major flaw in your plan – it will never work.
▶️ People: He’s the perfect boyfriend; his only flaw is the fact that he sometimes
speaks without thinking.
The word defect also refers to a problem, usually when a mechanical or
manufactured item was produced with the problem. We often use the adjective
defective.
▶️ Defects in the machinery caused several fires to break out in the factory.
▶️ This camera is defective – the flash doesn’t work. I’ll need to exchange it.
When a baby is born having something wrong or not normal with its body, this is
called a birth defect.
The word fault refers to responsibility for a problem or mistake. It’s usually used
with “my/your/his/her fault” or to say that a person/company is “at fault” for the
problem.
▶️The car accident was his fault because he drove through a red light.
▶️ The giant factory is at fault for the air pollution in this area.
You can also use the word faults to talk about problems with people’s character in
general, as in the expression, “Everyone has their faults.”