Obstacle regarding title (5)
I believe the answer is:
baron
'title' is the definition.
(I have seen 'Aristocratic title' mean 'baron' so perhaps 'title' could also mean 'baron')
'obstacle regarding' is the wordplay.
'obstacle' becomes 'bar' (I've seen this before).
'regarding' becomes 'on' (I can't explain this - if you can you should believe this answer much more).
'bar'+'on'='BARON'
Can you help me to learn more?
(Other definitions for baron that I've seen before include "powerful man owning lots of dailies?" , "Powerful financier" , "An English lord or a magnate" , "Noble rank" , "Minor noble" .)