Flatter male TV personage in the bar, last of all (6)
I believe the answer is:
evener
'flatter' is the definition.
('even' can be similar in meaning to 'flat')
'male tv personage in the bar last of all' is the wordplay.
'last of all' says to take the final letters.
The last letters of 'male tv personage in the bar' are 'EVENER'.
(Other definitions for evener that I've seen before include "Flatter" , "More level" , "One should smooth out" , "Calmer" , "Smoother" .)