If something niggles you, it causes you to worry slightly over a long period of time.
例句
I realise now that the things which used to niggle and annoy me just don't really matter...我現在意識到那些曾令我煩惱不快的事情其實無關緊要。It's been niggling at my mind ever since I met Neville in Nice...自從在尼斯見到內維爾后，我一直忐忑不安。
VERB
對…吹毛求疵;挑剔
If someone niggles you, they annoy you by continually criticizing you for what you think are small or unimportant things.
例句
I don't react anymore when opponents try to niggle me...對手找茬惹我時，我不會再理他們。You tend to niggle at your partner, and get hurt when he doesn't hug you.你往往會對伴侶吹毛求疵，如果他不擁抱你，就感到受了傷害。
英英詞典釋義
Verb
1. worry unnecessarily or excessively;
"don't fuss too much over the grandchildren--they are quite big now"