I'm English learner in Korea.
In Korean, "blatant" and "flagrant" has no difference.
However, the Word Smart 6th edition told me, don't confuse them.
But I can't get the difference between them.
Can you explain it with some examples?
Of course "blatant" and "flagrant" are not the same in Korean, because they are not Korean words! What you mean is "my dictionary translates both to the same Korean word".
This is because they do have very similar and overlapping meanings in English, and there are lots of times when you could use either.
Blatant means "obvious", (originally it meant "making a loud noise). If something is so obvious that it is annoying you can call it blatant.
Flagrant means offensive or outrageous. (It comes from a word meaning "on fire") If something is so offensive that it obvious you can call it "flagrant"
In very many situations you could use either.
Some examples from football:
He punched the football away with his hand, that was a blatant handball. Why didn't the referee see it??
That was a sliding tackle with both feet, and took the player out. It was a flagrant foul. It should have been a red card!
Source http://grammarist.com/usage/blatant-flagrant/ Has more examples