Ulcers troubled English hermit (7)
I believe the answer is:
recluse
'hermit' is the definition.
(synonyms)
'ulcers troubled english' is the wordplay.
'troubled' indicates anagramming the letters.
'english' becomes 'E' (abbreviation as in OED).
'ulcers' is an anagram of 'reclus'.
'reclus'+'e'='RECLUSE'
(Other definitions for recluse that I've seen before include "One who avoids people, like hermit" , "One lives in solitude" , "Solitary individual" , "Person who lives alone and avoids people" , "Person who lives alone and avoids others" .)