Contrite writer I shelter (8)
I believe the answer is:
penitent
'contrite' is the definition.
(similar in meaning)
'writer i shelter' is the wordplay.
'writer' becomes 'pen' (something which writes).
'shelter' becomes 'tent' (canvas shelter).
'pen'+'i'+'tent'='PENITENT'
(Other definitions for penitent that I've seen before include "He's sorry for his sins" , "Expressing sorrow for one's sins" , "Feeling regret for one's sins" , "Showing remorse" , "I'm sorry" .)