Killjoy takes booty to harbour (10)
I believe the answer is:
spoilsport
'killjoy' is the definition.
('spoilsport' can be a synonym of 'killjoy')
'booty to harbour' is the wordplay.
'booty' becomes 'spoils' (I've seen this before).
'to harbour' becomes 'port' (I've seen this before).
'spoils'+'port'='SPOILSPORT'
'takes' acts as a link.
(Other definitions for spoilsport that I've seen before include "One who won't play?" , "misery" , "Party pooper" , "Person marring others' pleasure" , "Killjoy" .)