Did judge desert extremely dry at first (5)
I believe the answer is:
rated
'did judge' is the definition.
(rating is a kind of judging)
'desert extremely dry at first' is the wordplay.
'desert' becomes 'rat' (abandon treacherously).
'at first' says to take the initial letters.
The first letters of 'extremely dry' is 'ed'.
'rat'+'ed'='RATED'
(Other definitions for rated that I've seen before include "Trade (anag.)" , "Censured" , "esteemed" , "Considered" , "Scolded, estimated" .)