Mind catching it in UK? (7)
I believe the answer is:
britain
'uk?' is the definition.
(synonyms)
'mind catching it' is the wordplay.
'mind' becomes 'brain' (synonyms).
'catching' means one lot of letters goes inside another.
'brain' placed around 'it' is 'BRITAIN'.
'in' acts as a link.
(Other definitions for britain that I've seen before include "See 10" , "England, Scotland, Wales and Northern Ireland" , "Main part of UK" , "Largest UK island" , "Main UK island" .)