What is the ruling on plucking eyebrows for a woman who was harmed in an accident during childhood, the effects of which are still present?

The basic principle regarding plucking (al-Namṣ) is that it is forbidden and considered one of the major sins, permissible only out of necessity.

Thus, there is no harm in removing some eyebrow hair if its presence causes a clear disfigurement, in order to avert this harm.