Arrive drunk round one 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 am not certain of the 'holiday' bit.
'arrive drunk round one' is the wordplay.
'drunk' is an anagram indicator.
'round' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'arrive' with letters rearranged gives 'rivera'.
'rivera' enclosing 'i' is 'RIVIERA'.
Can you help me to learn more?
(Other definitions for riviera that I've seen before include "Nice location" , "I arrive at southern resort area in France" , "I arrive at rich resort in Southern France" , "Coastal area between Cannes and Italy" , "Subtropical 1 dn area" .)