Occasions when I’m stuck in a setback (5)
I believe the answer is:
times
'occasions' is the definition.
(I've seen this before)
'i'm stuck in a setback' is the wordplay.
'i'm' becomes 'im' (**).
'stuck in' indicates putting letters inside.
'a setback' becomes 'tes' (I've seen this in other clues).
'im' placed into 'tes' is 'TIMES'.
'when' is the link.
(Other definitions for times that I've seen before include "See 10" , "See 1" , "- - they are a-changin'" , "Square in New York" , "Thunderer?" .)