I'm not sure journalist's stalking ability is exhausted (9)
I believe the answer is:
knackered
'is exhausted' is the definition.
(I've seen this before)
'i'm not sure journalist's stalking ability' is the wordplay.
I cannot really understand how this works, but
'ability' could be 'knack' (knack is a kind of ability) and 'knack' is found within the answer.
'journalist' could be 'ed' (short for editor) and 'ed' is present in the answer.
'i'm not sure' could be 'er' (expression of hesitation) and 'er' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for knackered that I've seen before include "Worn out" , "Exhausted (slang)" .)