Time rope expert set off (7)
I believe the answer is:
trigger
'set off' is the definition.
(synonyms)
'time rope expert' is the wordplay.
I cannot really see how this works, but
'time' could be 't' (abbreviation) and 't' is found within the answer.
The remaining letters 'rigger' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for trigger that I've seen before include "Lever on gun" , "Lever to activate firing mechanism" , "Pull it to discharge gun" , "Cause (device) to operate" , "make things happen" .)