A:A lady should not trim her eyebrows, get it trimmed by someone else, nor should she trim the eyebrows of others. The Hadeeth has forbidden these acts and such people have been cursed in the Hadeeth. (Al Bahrur Raa’iq V16 P78)
Threading will also not be permitted because it is imitation of non Muslims and this too has been forbidden in Hadeeth.
Allah Ta’aala knows best.
Mufti Siraj Desai