I arrive drunk in holiday region (7)
I believe the answer is:
riviera
'holiday region' is the definition.
'riviera' can be an answer for 'region' (I have seen 'Coastal region ' mean 'riviera' so perhaps 'region' could also mean 'riviera'). I'm not sure about the 'holiday' bit.
'i arrive drunk in' is the wordplay.
'drunk' indicates anagramming the letters.
'in' is an insertion indicator.
'arrive' anagrammed gives 'rivera'.
'i' placed into 'rivera' is 'RIVIERA'.
Can you help me to learn more?
(Other definitions for riviera that I've seen before include "Subtropical coastal area" , "I arrive at rich resort in Southern France" , "Mediterranean playground of the rich" , "Coastal region with resorts" , "popular holiday area" .)