Last name Жастин (Jastin 
, Castin 
, Жастин) , in the entire world, is quite a common cognomen. The cognomen Жастин is habitual in Tanzania, where it is quite a rare surname, Haiti, and Belgium. Measured by absolute frequency, it most frequently occurs in Tanzania, Philippines, and India. More prevalently, Жастин is the forename as well as the last name.