Think it was Abu Dharr but I'm not sure though.
Assalaamu alaykum, I think it was Sayyiduna Abu Dardaa radiyAllahu 'anhu who was known as Hakeem al-Ummah.
In Siyar A’lam al-Nubala’, Imam Dhahabi mentioned in the tarjamah for Abu Darda’, فقال فيه الإمام الرباني وكان يقال هو حكيم هذه الأمة
I think its the title given for Moulana Ahraf Ali Thanvi R.A
Bro Abdul-Bari broke the suspense with the right answer. It's a technicality or he deserves to be awarded.