Island previously to get motorway round it (7)
I believe the answer is:
formosa
'island previously' is the definition.
(former name of Taiwan)
'motorway round it' is the wordplay.
'motorway' becomes 'form' (I can't explain this - if you can you should give a lot more credence to this answer).
'round' becomes 'o' (round can mean a round object).
'it' becomes 'sa' (old-fashioned abbreviation for sex appeal).
'form'+'o'+'sa'='FORMOSA'
'to get' acts as a link.
(Other definitions for formosa that I've seen before include "Old name of island" , "Taiwan, formerly" , "Old name for Taiwan" , "Former name of Taiwan" .)