Was the big one universally original? (4)
I believe the answer is:
bang
'universally original?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'was the big one' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bang that I've seen before include "Explosive noise" , "Report - something the hairdresser did?" , "hit" , "Sudden loud noise like an explosion" , "precisely" .)