It's posh abroad, one argues (7)
I believe the answer is:
sophist
'one argues' is the definition.
I can't judge whether this definition defines the answer.
'it's posh abroad' is the wordplay.
'abroad' is an anagram indicator (abroad can mean moving around).
'its'+'posh'='itsposh'
'itsposh' with letters rearranged gives 'SOPHIST'.
Can you help me to learn more?
(Other definitions for sophist that I've seen before include "One who uses clever but false argument" , "one might plausibly argue" , "Clever but fallacious reasoner" , "One using clever but wrong arguments" , "One given to specious reasoning" .)