Help a troubled character abroad (5)
I believe the answer is:
aleph
'character abroad' is the definition.
(letter of the Hebrew alphabet)
'help a troubled' is the wordplay.
'troubled' indicates an anagram.
'help'+'a'='helpa'
'helpa' with letters rearranged gives 'ALEPH'.
(Other definitions for aleph that I've seen before include "Abroad, a" , "Sign of a beast? A Phoenician" , "Hebrew character" , "First letter of the Hebrew alphabet" , "letter in Middle East" .)