adjective
1
BAD : Water is very rare in some parts of the country.
GOOD : Water is very scarce in some parts of the country.
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If certain things are rare there are only a few of them in existence: 'Rare coins are usually worth a lot of money.' A rare event is one that hardly ever happens: 'I was lucky enough to witness one of her rare public appearances.'
To describe something that is usually common but for some reason is difficult to obtain at a particular time or in a particular place, use scarce : 'After the war, food and clothing were scarce.'
2
BAD : I think that my name is rare.
GOOD : I think that my name is unusual.
BAD : In San Francisco I saw some rare architecture.
GOOD : In San Francisco I saw some unusual architecture.
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If something is different from what is usual, it is unusual : 'The bread had an unusual flavour.' 'Kit. That's an unusual name.'
3
BAD : It is not rare that women have a job nowadays.
GOOD : It is not unusual for women to have a job nowadays.
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not unusual ( for sb ) to do sth (NOT not rare ): 'It's not unusual to see business people cycling to work these days.'