I was taught that we do not shave cut hair or nails motzey shabbos. Is this halachah?
It is true that there are people that say that we shouldn’t cut nails or take a haircut on Motzei Shabbos, however it is not halacha, and I haven’t found anyone that says this as halacha, but it might be some people’s minhag at best. The reason for it, is most probably because we are to groom ourselves properly before Shabbos, and by doing it right after Shabbos it is showing that we didn’t groom ourselves properly before Shabbos.
Kovetz Halachos )Shabbos -1( Pg. 789.