There's no advantage in having two (5)

I believe the answer is:

deuce

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'two' is the definition.
(synonyms)

I don't understand the rest of the clue.

(Other definitions for deuce that I've seen before include "More than one" , "with equal score" , "situation of no advantage to either side" , "score, forty apiece" , "score at Wimbledon?" .)

I've seen this clue in The Irish Independent.

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