Japanese island acceptable to a certain extent, docked (7)
I believe the answer is:
okinawa
'japanese island' is the definition.
(I've seen this before)
'acceptable to a certain extent docked' is the wordplay.
'acceptable' becomes 'ok'.
'to a certain extent' becomes 'inaway' (I've seen this before).
'docked' means to remove the last letter (to dock can mean to remove the tail of an animal).
'inaway' with its final letter taken off is 'inawa'.
'ok'+'inawa'='OKINAWA'
(Other definitions for okinawa that I've seen before include "island out east" , "Japanese island, capital Naha" , "Japanese location" , "Region of southern Japan, scene of fierce fighting in 1945" , "coral island" .)