Repugnant sailor with house by river split (9)
I believe the answer is:
abhorrent
'repugnant' is the definition.
(synonyms)
'with house by river split' is the wordplay.
'with' indicates putting letters inside.
'house' becomes 'h'.
'by river' becomes 'abor' (I can't justify this - if you can you should give a lot more credence to this answer).
'split' becomes 'rent' (past tense of 'rend' meaning to split).
'h' put inside 'abor' is 'abhor'.
'abhor'+'rent'='ABHORRENT'
'sailor' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for abhorrent that I've seen before include "Earthborn (anag) - detestable" , "Horrible" , "hateful" , "Detestable, loathsome" , "Inspiring disgust and loathing" .)