毛病

Etymology
“Defects in a horse's hair” > “fault; defect; problem; disease”.

Noun

 * 1)  defects in a horse's hair; abnormality in the fur colour of domestic animals
 * 2) fault; defect; breakdown; trouble; mishap
 * 3) personal flaw; shortcoming
 * 4)  illness; medical problem; condition; disease; ailment
 * 1)  illness; medical problem; condition; disease; ailment