Criticise over petty details (6)

I believe the answer is:
niggle
(Other definitions for niggle that I've seen before include "Persistant annoyance" , "Grumble" , "Trivial problem, fuss" , "Cause minor persistent annoyance" , "Get" .)
I believe the answer is:
niggle
(Other definitions for niggle that I've seen before include "Persistant annoyance" , "Grumble" , "Trivial problem, fuss" , "Cause minor persistent annoyance" , "Get" .)