Put down, ahead of cheers, in harbour (9)
I believe the answer is:
entertain
'harbour' is the definition.
('entertain' can be a synonym of 'harbour')
'put down ahead of cheers in' is the wordplay.
'put down' becomes 'enter' ('enter' can be a synonym of 'put down'**).
'ahead of' says to put letters next to each other (I've seen this in other clues).
'cheers' becomes 'ta' (I've seen this in other clues).
'enter'+'ta'+'in'='ENTERTAIN'
(Other definitions for entertain that I've seen before include "can be amusing" , "Have company" , "Amuse, divert" , "Act as host" , "Have a mind to - have a party" .)