ならず者 refers to a ruffian or hoodlum, often implying violence or lawlessness, whereas 極道者 emphasizes moral depravity and a dissolute lifestyle.
Etymology
Compound of 極道 (gokudō, 'wickedness; depravity') + 者 (mono, 'person'). The exact origin of 極道 is uncertain, but it is used in compounds to denote extreme moral corruption.
