White, as opposed to red, dresses kept in dry (7)
I believe the answer is:
tsarist
'white as opposed to red' is the definition.
I can't tell whether this definition defines the answer.
'dresses kept in dry' is the wordplay.
'dresses' becomes 'saris' (sari is a kind of dress).
'kept in' indicates putting letters inside.
'dry' becomes 'tt' (abbreviation for teetotal).
'saris' inserted into 'tt' is 'TSARIST'.
Can you help me to learn more?
(Other definitions for tsarist that I've seen before include "One supporting ruler" , "Like Russia once" , "Artists (anag.); supporter of Russian emperor" , "Of emperors of old Russia" , "Russian emperor's supporter" .)