Promotes practicable issue originally from elsewhere? (6-3)

I believe the answer is:

foster-son

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'promotes practicable' is the definition.
I can't tell whether this defines the answer.

'issue originally from elsewhere?' is the wordplay.
'issue' becomes 'son' (issue can mean someone's offspring).
'originally' is a charade indicator (letters next to each other) (some letters go before others).
'from elsewhere?' becomes 'foster' (I am not sure about this - if you are sure you should believe this answer much more).
'son' put after 'foster' is 'FOSTER-SON'.

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