Area covering Thailand, miles away? (4)
I believe the answer is:
asia
'area' is the definition.
(I have seen 'Large area' mean 'asia' so perhaps 'area' could also mean 'asia')
'covering thailand miles away?' is the wordplay.
'covering' becomes 'asi' (I can't explain this - if you can you should give a lot more credence to this answer).
'thailand' becomes 'siam' (synonyms).
'miles' becomes 'mis' ('mi' can be a synonym of 'mile').
'away?' suggests deleting specific letters.
'siam' with 'mis' taken out is 'a'.
'asi'+'a'='ASIA'
Can you help me to learn more?
(Other definitions for asia that I've seen before include "The Orient" , "huge amount of ground" , "space for economic expansion?" , "Major land mass" , "Thailand and its location" .)