Lawsuit can be a nuisance (5)
I believe the answer is:
trial
I believe this is a double definition.
'lawsuit' is the first definition.
(thesaurus)
'a nuisance' is the second definition.
(both can mean something annoying)
'can be' acts as a link.
(Other definitions for trial that I've seen before include "nuisance" , "Hearing - test" , "Troublesome thing; test" , "competition" , "Annoyance" .)