Glen cuddles Unionist rogue for entertainment (10)
I believe the answer is:
vaudeville
'entertainment' is the definition.
(I've seen this before)
'glen cuddles unionist rogue' is the wordplay.
'glen' becomes 'vale' (I've seen this in other clues).
'cuddles' is an insertion indicator.
'unionist' becomes 'u' (abbreviation as in Democratic Unionist Party).
'rogue' becomes 'devil'.
'u'+'devil'='udevil'
'vale' going around 'udevil' is 'VAUDEVILLE'.
'for' acts as a link.
(Other definitions for vaudeville that I've seen before include "Variety entertainment" , "Musical and comedy entertainment" , "variety show" , "theatrical entertainment" , "American music hall" .)