Write-up about harbour (6)
I believe the answer is:
report
'write-up' is the definition.
(thesaurus)
'about harbour' is the wordplay.
'about' becomes 're' (regarding).
'harbour' becomes 'port' (I've seen this before).
're'+'port'='REPORT'
(Other definitions for report that I've seen before include "Formal statement" , "Inform about the sound of thegun" , "Write-up" , "Written account" , "Complain about - account" .)