It's a trigger to thrash judge, according to Spooner (8)
I believe the answer is:
tripwire
'spooner' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?
'it's a trigger to thrash judge' is the wordplay.
I cannot quite understand how this works, but
'trigger' could be 'trip' (synonyms) and 'trip' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is present in the answer.
This explanation may well be incorrect...
'according to' is the link.
Can you help me to learn more?
(Other definitions for tripwire that I've seen before include "Trigger for trap/bomb" , "One setting off" , "Device working a trap or alarm when stumbled over" , "Trigger for booby trap" , "that could trigger alarm" .)