Used to describe an amazingly cool person in the south of England but refers to a moronic retard in the North, Wales and Scotland. Can be used to mean beer in Ireland and in most places of the UK
Person 1: How's your time in Manchester ?
Person 2: Fine apart from my new room mate is a complete jackalaka
Person 1: Thats a shame. Maybe you should throw him out the window whilst you sleep
Person 2: That's a bit mean. He isn't that bad a jackalaka unlike my classmate Jack.