One up on a soap box or a hill (6)
I believe the answer is:
'one up on a soap box' is the definition.
I can't tell whether this definition defines the answer.
'or a hill' is the wordplay.
'hill' becomes 'tor' (tor is a kind of hill).
Can you help me to learn more?
(Other definitions for orator that I've seen before include "A Rhetorical talker or speech-maker" , "A fluent public speaker" , "I declaim" , "Eloquent type" , "One addressing" .)