Modern communication needs a new start? Humbug! (5)

I believe the answer is:

sweet

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'start? humbug' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for sweet that I've seen before include "darling" , "Ewes cycle it (anag) -- herb (myrrh)" , "Cute" , "Toffee, e.g." , "Pudding" .)

I've seen this clue in The Guardian.

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