Cites a problem about hermit (7)
I believe the answer is:
ascetic
'hermit' is the definition.
(I've seen this before)
'cites a problem about' is the wordplay.
'problem' indicates an anagram.
'about' becomes 'c' (circa).
'cites'+'a'='citesa'
'citesa' with letters rearranged gives 'asceti'.
'asceti'+'c'='ASCETIC'
(Other definitions for ascetic that I've seen before include "Person who practises self-denial as spiritual discipline" , "Self-denying person who shuns ordinary pleasures" , "One abstaining from worldly comforts" , "recluse" , "Eremite" .)