" 'How long is a piece of string?' is a nonsense question not because there is no such thing as a piece of string, nor because a given piece of string has an indeterminate length. It is a nonsense question because it fails to define which piece of string is being talked about. 'WHo made God ' is unanswerable for the same basic reason - the word 'God' is left undefined. What if we define 'God' as 'the uncreated creator of all things'? Then the nonsense of the question becomes immediately obvious - 'Who created the uncreated one?'
Edgar Andrews 'Who made God?'