BT Tan 11a(49) :הוא דמדכי נפשיה‏ : it is because he purifies himself (that he is called holy)
See the entire entry for dky vb. to be clean

BT Tan 11a(49) :דמסאב נפשיה‏ : one who makes himself ritually unclean (by contact with a corpse)
See the entire entry for sˀb vb. D to defile, to dirty