Crossword Genius

Fish has to dry up (6)

Ross

I believe the answer is:

turbot

'fish' is the definition.
(turbot is a kind of fish)

'to dry up' is the wordplay.
'dry' becomes 'brut' (type of wine).
'up' is a reversal indicator (in down clue: letters go upwards).
'to'+'brut'='tobrut'
'tobrut' written backwards gives 'TURBOT'.

'has' is the link.

(Other definitions for turbot that I've seen before include "Pale brown, speckled flatfish" , "Large brownish European flatfish" , "Species of flatfish" , "Expensive flatfish" , "Large succulent flatfish" .)

I've seen this clue in The Telegraph.
Want a hint initially instead of a full solution? Install my app