Careless mistakes with house finally fixed (8)
I believe the answer is:
slipshod
'careless' is the definition.
(similar in meaning)
'mistakes with house finally fixed' is the wordplay.
'mistakes' becomes 'slips' ('slip' can be a synonym of 'mistake').
'with' says to put letters next to each other.
'house' becomes 'ho' (abbreviation for house).
'finally' says to take the final letters.
The final letter of 'fixed' is 'd'.
'slips'+'ho'+'d'='SLIPSHOD'
(Other definitions for slipshod that I've seen before include "Sloppy and haphazard" , "Carelessly done" , "Careless and slapdash, bad work" , "Careless in thought or organisation" , "Lacking in care" .)