Someone, female, who behaves in the oddest ways, with great harm to others, and for no reason, but just because they can, and, despite whatever they may profess, in the end care only about themselves.

a phrase chiefly used in northern England.

it is a contracted form of "it'll be reet", where "reet" means "alright" or "OK".

living your life according to "be reet" is the only way to find happiness in life.