Greedy person — upset of course (4)

I believe the answer is:

wolf

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'greedy person' is the definition.
'wolf' can be an answer for 'person' (wolf is a kind of person). I am unsure of the 'greedy' bit.

'upset of course' is the wordplay.
'upset of' says the letters should be written in reverse (I've seen 'upset' mean this).
'course' becomes 'flow' (synonyms).
'flow' reversed gives 'WOLF'.

Can you help me to learn more?

(Other definitions for wolf that I've seen before include "Carnivorous pack animal" , "Pack animal; composer" , "Carnivorous mammal" , "Eat hastily" , "Lupine mammal" .)

I've seen this clue in The Times.

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