Public notices hint of hesitation here (5)

I believe the answer is:

adsum

I'm a little stuck... Click here to teach me more about this clue!

'here' is the definition.
(I've seen this before)

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

(Another definition for adsum that I've seen is " here".)

I've seen this clue in The Times and The Sunday Times.

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