A grave old doctor sees big killer (4-4)

I believe the answer is:

atom-bomb

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'big killer' is the definition.
'atom bomb' can be an answer for 'killer' (I've seen this before). I am not sure about the 'big' bit.

'a grave old doctor' is the wordplay.
'grave' becomes 'tomb' (synonyms).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'doctor' becomes 'MB' (Bachelor of Medicine).
'a'+'tomb'+'o'+'mb'='ATOM-BOMB'

'sees' is the link.

Can you help me to learn more?

I've seen this clue in The Sun.

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