Engaged outspoken Asian political party (4,2)
I believe the answer is:
tied up
'engaged' is the definition.
(synonyms)
'outspoken asian political party' is the wordplay.
'outspoken' shows a homophone (sound like).
'asian' becomes 'thai' (Thailand is in Asia).
'political party' becomes 'DUP' (Democratic Unionist Party).
'thai' is a homophone of 'tie'.
'tie'+'dup'='TIED UP'
(Other definitions for tied up that I've seen before include "Secured; engaged" , "busy" , "Thus prisoner may be kept" .)