noun
1
BAD : These bombs could lead to the destruction of the mankind.
GOOD : These bombs could lead to the destruction of mankind.
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mankind (= the human race) WITHOUT the : 'Travelling into space was a great advance for mankind.'
2
DUBIOUS : The nature of mankind is very complicated.
GOOD : Human nature is very complicated.
DUBIOUS : In art we discover the beauty of mankind's imagination.
GOOD : In art we discover the beauty of the human imagination.
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Mankind (or the human race ) refers to all human beings considered as a group: 'The greatest danger to mankind is not science but ignorance.' 'These are the most devastating weapons mankind has ever devised.' 'What is mankind's long-term role in space?'
When you mean 'belonging to or typical of people (as opposed to God, animals, machines etc)', the usual pattern is human + noun: 'Greed and envy are common human failings.'
Note that phrases such as human nature, human error, human interest and human weakness are very common.