Dreadful cost I accepted uncomplaining (5)
I believe the answer is:
stoic
'uncomplaining' is the definition.
(I've seen this in another clue)
'dreadful cost i accepted' is the wordplay.
'dreadful' is an anagram indicator.
'accepted' means one lot of letters goes inside another.
'cost' is an anagram of 'stoc'.
'stoc' placed around 'i' is 'STOIC'.
(Other definitions for stoic that I've seen before include "he's not complaining" , "One indifferent to fortune, pleasure and pain" , "Athenian philosopher" , "show little emotion" , "Impassive type" .)