The Spectator's maxim? (9)

I believe the answer is:

watchword

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'the spectator's maxim?' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

This is the entire clue.

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(Other definitions for watchword that I've seen before include "Slogan" , "rallying-cry" .)

I've seen this clue in The Sun.

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