Motorway circling a large West African country (4)
I believe the answer is:
mali
'west african country' is the definition.
(I've seen this before)
'motorway circling a large' is the wordplay.
'motorway' becomes 'mi' (resembles M1, English motorway).
'circling' indicates putting letters inside (circling can mean going around or containing).
'large' becomes 'l'.
'a'+'l'='al'
'mi' enclosing 'al' is 'MALI'.
(Other definitions for mali that I've seen before include "West African country, capital Bamako" , "Send mail out to Africa" , "African country, once French Sudan" , "African country, former French colony" , "A state" .)