Contrast with Clean.
Unclean Animals
7 days before the flood waters came, the Lord told Noah to go into the ark with his household and 1 pair of each unclean animal.
"Go into the ark, you and all your household, for I have seen that you are righteous before me in this generation. Take with you seven pairs of all clean animals, the male and his mate, and a pair of the animals that are not clean, the male and his mate, and seven pairs of the birds of the heavens also, male and female, to keep their offspring alive on the face of all the earth. For in seven days I will send rain on the earth forty days and forty nights, and every living thing that I have made I will blot out from the face of the ground."
During the flood, all flesh died apart from those who were with Noah in the ark.