Communist country bridge player's declared vocation (5,5)
I believe the answer is:
north korea
'communist country' is the definition.
(North Korea has a communist government)
'bridge player's declared vocation' is the wordplay.
'bridge player' becomes 'north' (bridge players are called north, south etc).
'declared' shows a homophone (sound like).
'vocation' becomes 'career' (vocation can mean a career or line of work).
'career' is a homophone of 'korea'.
'north'+'korea'='NORTH KOREA'
(Other definitions for north korea that I've seen before include "secretive country" , "Country bordering China" , "Reclusive state" , "Land" .)