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Etymology
From 🇰🇲; from 's categorisation of persons into four types based on their intelligence:
 * 1) persons of excellent intelligence, capable of understanding things quickly, are like lotuses above the water, which will bloom immediately once hit by sunlight;
 * 2) persons of average intelligence, requiring further training or education in order to understand things better, are like lotuses at the water's edge, waiting to come above the water in the near future;
 * 3) persons of low intelligence, requiring more diligence and perseverance than usual in order to understand things, are like lotuses under the water, still having hope to come above the water;
 * 4) persons of no intelligence, yet lacking diligence and perseverance in developing oneself, are like lotuses under (or buried in) the mud, hopelessly unable to grow up to get sunlight.

Noun

 * 1)  person of low intelligence; stupid person; idiot.