Tougher newcomer swaps ace for five of diamonds? (8)

I believe the answer is:

stronger

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'tougher' is the definition.
('strong' can be a synonym of 'tough')

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for stronger that I've seen before include "More potent" , "More robust" , "More resolute" , "Having greater power" , "More powerful" .)

I've seen this clue in the Sydney Morning Herald.

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