Imagined debtor pressing soft mate (6)

I believe the answer is:

dreamt

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'imagined' is the definition.
(dream up can mean to imagine)

I cannot understand how the rest of the clue works.

(Other definitions for dreamt that I've seen before include "Had mind pictures while asleep" , "Imagined" , "Fantasised" , "Fancied" , "Vainly hoped" .)

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

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