Emphasizes a small problem's persistent nature, which can affect mood or performance over time. The niggling error in the report eventually led to a bigger issue.
Pro Tip 2/3
Not Serious
Usually not a serious problem but can be distracting or cause slight annoyance. She had a niggling concern about the decorations not being perfect.
Pro Tip 3/3
Emotional Tinge
Can imply an emotional disturbance like irritation or uneasiness beyond physical discomfort. A niggling sense of unease kept him awake at night.