Old beset by criticism, mostly long-suffering (5)
I believe the answer is:
stoic
'long-suffering' is the definition.
(stoic can mean brave when suffering)
I cannot understand how the rest of the clue works.
(Other definitions for stoic that I've seen before include "Impassive type" , "One who doesn't complain" , "Uncomplaining person" , "Long-suffering type; follower of Zeno" , "Ancient philosopher" .)