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 quite see 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 found within the answer.
'i'm not sure' could be 'er' (expression of hesitation) and 'er' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for knackered that I've seen before include "Worn out" , "Exhausted (slang)" .)