niggling
/ˈnɪglɪŋ; `nɪɡlɪŋ/ adj
1 too unimportant to give time or attention to; trifling 不值得费时或操心的; 无关紧要的; 琐碎的
Don't waste time on niggling details. 不要为琐事浪费时间.
2 annoying in a minor but persistent way 令人烦恼的, 讨厌的（事不大但不断）
a niggling pain 烦人的疼痛
niggling criticism 恼人的批评.