Item about stream is action-packed (9)
I believe the answer is:
thrilling
'action-packed' is the definition.
Both the answer and definition are adjectives.
Maybe there's an association between them I don't understand?
'item about stream' is the wordplay.
'item' becomes 'thing' (both can mean an object).
'about' is an insertion indicator.
'stream' becomes 'rill' (rill is a kind of stream).
'thing' enclosing 'rill' is 'THRILLING'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for thrilling that I've seen before include "Hair-raising" , "Gripping" , "Causing pleasurable excitement" , "Sensational" , "Extremely exciting" .)