Thieving sailor is at heart corrupt (4)

I believe the answer is:

evil

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'corrupt' is the definition.
(I've seen this in another clue)

'thieving sailor is at heart' is the wordplay.
'thieving' becomes 'ev' (I can't explain this - if you can you should give a lot more credence to this answer).
'is at heart' says to take the centre.
The central letters of 'sailor' are 'il'.
'ev'+'il'='EVIL'

Can you help me to learn more?

(Other definitions for evil that I've seen before include "Morally bad" , "Profoundly immoral" , "Live badly in depravity" , "Immorality" , "Malign" .)

I've seen this clue in The Irish Times.

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