Understanding blame attached to harbour (7)
I believe the answer is:
rapport
'understanding' is the definition.
(thesaurus)
'blame attached to harbour' is the wordplay.
'blame' becomes 'rap' ('rap' can be a synonym of 'blame').
'attached to' is a charade indicator (letters next to each other).
'harbour' becomes 'port' (I've seen this before**).
'rap'+'port'='RAPPORT'
(Other definitions for rapport that I've seen before include "Pro rapt with fellow feeling" , "Emotional bond" , "Harmonious understanding with someone" , "Harmonious relationship between two people" , "Feeling of sympathy and understanding" .)