1nig·gle 
/ˈnɪgəl/ verb
nig·gles; nig·gled; nig·gling /ˈnɪgəl/ verb Brit 1 : to worry or annoy (someone) [+ obj] ▪ She had been niggled by worry her entire life. ▪ It really niggles [=bothers, bugs] me that she didn't call. [no obj] — often + at ▪ One question continued to niggle [=nag] at him. 2 [no obj] : to argue or make criticisms about something that is not important
▪ He's always niggling over small details.
▪ He's always niggling over small details.
