One ancient barbarian in a hundred (3)
I believe the answer is:
hun
'barbarian in a hundred' is the definition.
'hun' can be an answer for 'barbarian' (I've seen this before). I am not certain of the 'in a hundred' bit.
'one ancient' is the wordplay.
I cannot really understand how this works, but
'one' could be 'un' (I've seen this in other clues) and 'un' is present in the answer.
A single letter 'h' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for hun that I've seen before include "Ancient invader" , "Warlike nomad" , "Attila was a notorious one" , "One of fourth to fifth century invaders of Europe" , "Eg, Attila" .)