Wise returned soldier back inside with new business advertising (7)

I believe the answer is:

signage

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'wise' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for signage that I've seen before include "Means of communication" , "Informative notices in general" .)

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

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