Writer left to tour huge wine region (5)
I believe the answer is:
mosel
'wine region' is the definition.
'mosel' can be an answer for 'wine' (I've seen this before). I am not sure about the 'region' bit.
'writer left to tour huge' is the wordplay.
'writer' becomes 'me' (the person who wrote the clues).
'left' becomes 'l' (common abbreviation).
'to tour' means one lot of letters goes inside another (to tour can mean to go around).
'huge' becomes 'os' (abbreviation for outsize).
'me'+'l'='mel'
'mel' going around 'os' is 'MOSEL'.
Can you help me to learn more?
(Another definition for mosel that I've seen is " Wine".)