Englishfor English speakers
serious
Adjective
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A problem or situation is serious if it is not funny or comical, but important.
This is a serious problem. We must do something.
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A person is serious if the person is not laughing or joking, but saying what they mean.
I see. When you said the room was empty, you were serious!
The woman's face looked serious, so I knew she was saying something important.
defect
Noun
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A defect in something is a mistake or problem that makes the thing not perfect.
This gem has a defect, so it is not worth much.
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A defect is something that is not perfect.
defect
Verb
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If you defect from a group or country, you leave it and join a different side.
In 1961, defected from Russia.