Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- The word used in the Hadith is nams in Arabic, which means plucking the eyebrows. The Prophet (peace and blessings be upon him) considered plucking as distorting the creation of Allah.
2- Scholars have concluded that if a person’s eyebrows are unusually thick or unwieldy, then he or she can straighten them out. This is not considered nams or plucking.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, answers this question in this short video:
https://www.facebook.com/IslamicInstituteOfToronto/videos/1117301928404578/
Almighty Allah knows best.
Source: Islamic Institute of Toronto