Crossword Genius

Something of singular impact (4)

Ross

I believe the answer is:

oner

I'm a little stuck... Click here to teach me more about this clue!

'something of' is the definition.
I can't judge whether this defines the answer.

'singular impact' is the wordplay.
'singular' becomes 'one' (synonyms).
'impact' becomes 'r' (I can't explain this - if you can you should believe this answer much more).
'one'+'r'='ONER'

Can you help me to learn more?

(Other definitions for oner that I've seen before include "Big blow" , "Remarkable thing" , "Out-of-date banknote" , "expert" , "A pound coin" .)

I've seen this clue in the Evening Standard.
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