Ex-president not entirely genuine politician (5)

I believe the answer is:

trump

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'ex-president' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

'not entirely genuine politician' is the wordplay.
'not entirely' means to remove the last letter.
'genuine' becomes 'true' (similar in meaning).
'politician' becomes 'MP' (Member of Parliament).
'true' with its last letter removed is 'tru'.
'tru'+'mp'='TRUMP'

Can you help me to learn more?

(Other definitions for trump that I've seen before include "High card" , "High-ranking card" , "reliable person" , "Playing card with designated added value" , "Trusty fellow (colloq.); ruff" .)

I've seen this clue in The Sun.

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