Can a women pluck or thread her eyebrows if it is very thick and bushy?
There is a hadith narrating that the Messenger of God Muhammad (pbuh) cursed the women practiced tattooing and the women who removed hair from their faces. (Bukhari, Libas, 84; Muslim, Libas, 120)
It is a matter of dispute among the scholars of Islamic jurisprudence which type of practices this hadith includes.
When we consider the hadith in the light of the verse about changing the creation (An-Nisa 4:119), we can say that this curse is related to those who pluck their whole eyebrow and have new eyebrows drawn with pen or other techniques instead of the natural ones. Therefore, it is permissible to pluck the excess hair of bushy eyebrows which causes the woman to look ugly. You should be careful with not going too far and changing the natural shape of your eyebrows.