I can't change, I've become idle (8)
I believe the answer is:
inactive
'idle' is the definition.
('inactive' can be similar in meaning to 'idle')
'i can't change i've' is the wordplay.
'change' indicates anagramming the letters.
'cant' with letters rearranged gives 'nact'.
'i'+'nact'+'ive'='INACTIVE'
'become' acts as a link.
(Other definitions for inactive that I've seen before include "lethargic" , "Not moving/working" , "Immobile, not working" , "Idle, showing no movement" , "Not doing anything, passive" .)