In the TV series 'Dragonball Z' a Super Saiya-jin is a member of the Saiyan race who has achieved a new level of power. Characterised by the person's hair turning gold/yellow and spiking up, also their power increases many times over. The Saiyan must be pure of heart to turn Super Saiya-jin (SSJ)
Demi Saiya-jin (Gohan, Trunks and Goten) turn Super Saiya-jin more easily.
Gokou is pure good.
Vegeta is pure evil.