Unimportant point in dock, perhaps (6)
I believe the answer is:
detail
I believe this is a double definition.
'unimportant point' is the first definition.
(eg a small detail)
'dock perhaps' is the second definition.
(de-tail could mean to dock or remove a tail)
'in' acts as a link.
(Other definitions for detail that I've seen before include "party" , "Describe fully, give particulars of" , "Relate minutely" , "Small fact or feature" , "Small detachment of troops or police on special assignment" .)