Gripping article about a brook (9)
I believe the answer is:
thrilling
'gripping' is the definition.
(I've seen this before)
'article about a brook' is the wordplay.
'article' becomes 'thing' (both can mean an object).
'about' is an insertion indicator.
'a brook' becomes 'rill' (I've seen this in another clue).
'thing' enclosing 'rill' is 'THRILLING'.
(Other definitions for thrilling that I've seen before include "Extremely exciting" , "Hair-raising" , "Sensational" , "Causing pleasurable excitement" , "Gripping" .)