Old president brave nun slammed (3,5)

I believe the answer is:

van buren

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'old president' is the definition.
'van buren' can be an answer for 'president' (I've seen this before). I'm unsure of the 'old' bit.

'brave nun slammed' is the wordplay.
'slammed' indicates an anagram.
'brave'+'nun'='bravenun'
'bravenun' with letters rearranged gives 'VAN BUREN'.

Can you help me to learn more?

(Another definition for van buren that I've seen is " President".)

I've seen this clue in The Independent.

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