Strident babbling about European trap (11)
I believe the answer is:
penetrating
'strident' is the definition.
(thesaurus)
'babbling about european trap' is the wordplay.
'babbling' becomes 'prating' (both can mean talking excessively).
'about' indicates putting letters inside.
'european' becomes 'E' (abbreviation e.g. EU).
'trap' becomes 'net' (net is a kind of trap).
'e'+'net'='enet'
'prating' placed around 'enet' is 'PENETRATING'.
(Other definitions for penetrating that I've seen before include "Incisive" , "Boring - keen" , "Going through" , "Acute" .)