Rather dry inside quarry (6)
I believe the answer is:
pretty
'rather' is the definition.
('pretty' can be a synonym of 'rather')
'dry inside quarry' is the wordplay.
'dry' becomes 'tt' (abbreviation for teetotal).
'inside' indicates putting letters inside.
'quarry' becomes 'prey' ('prey' can be a synonym of 'quarry').
'tt' placed inside 'prey' is 'PRETTY'.
(Other definitions for pretty that I've seen before include "chocolate-box" , "pulchritudinous" , "Fair - fairly" , "like a kettle of fish" , "Pleasing to look at" .)