In poor condition, part of rectum bled - Ow! Nasty! (10)
I believe the answer is:
tumbledown
'in poor condition' is the definition.
(tumbledown means in poor condition)
'part of rectum bled ow nasty' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'TUMBLEDOWN' is hidden within 'rectum bled ow nasty'.
(Other definitions for tumbledown that I've seen before include "Ruined" , "threatening to fall" , "threatening to collapse" , "neglected" , "Derelict" .)