Plaintiff’s ruse is silly (4)
I believe the answer is:
suer
'plaintiff's' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?
'ruse is silly' is the wordplay.
'is silly' is an anagram indicator.
'ruse' is an anagram of 'SUER'.
Can you help me to learn more?
(Other definitions for suer that I've seen before include "person in court" , "One in court, perhaps" , "One seeking redress" .)