Sweeping gutter outside house (8)
I believe the answer is:
thorough
'sweeping' is the definition.
('thorough' can be a synonym of 'sweeping')
'gutter outside house' is the wordplay.
'gutter' becomes 'trough' ('trough' can be a synonym of 'gutter').
'outside' is an insertion indicator.
'house' becomes 'ho' (abbreviation for house).
'trough' placed around 'ho' is 'THOROUGH'.
(Other definitions for thorough that I've seen before include "Complete, absolute" , "Attentive to detail" , "Doing things with great attention to detail" , "Total - painstaking - in-depth" , "Out-and-out, utter" .)