Regretful writer, one with temporary accommodation (8)
I believe the answer is:
penitent
'regretful' is the definition.
(I've seen this in another clue)
'writer one with temporary accommodation' is the wordplay.
'writer' becomes 'pen' (something which writes).
'one' becomes 'i' (Roman numeral).
'with' is a charade indicator (letters next to each other).
'temporary accommodation' becomes 'tent' (people stay in a tent temporarily).
'pen'+'i'+'tent'='PENITENT'
(Other definitions for penitent that I've seen before include "Teen pint (anag.)" , "Regretting one's wrongdoings" , "Repentant" , "Rueful" , "I'm sorry" .)