Diviner, though not more heavenly (6)

I believe the answer is:

dowser

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'diviner' is the definition.
(I know that dowser is a type of diviner)

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

Can you help me to learn more?

(Other definitions for dowser that I've seen before include "Person seeking water using hazel stick" , "He searches for water using hazel rod" , "One prospecting for water" , "One who searches for underground water" , "Water diviner" .)

I've seen this clue in The Irish Independent.

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