Noun, word used to describe really filthy, manky, disgusting living conditions, not necessarily inhabited by 'ferals'. Such living conditions transcend normal grossness and are rampantly foul. Ferality can be seen in some student flats and at campsites at music festivals. Also used to describe the way of life and attitude that accompanies such living conditions.
When you use an empty bacon packet as a plate and a lighter as a fork and make bongs out of salamis (and use them), you know you're living in ferality.