Ambassadorial function to land-lock vessel inside (7)
I believe the answer is:
embassy
'ambassadorial function' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'land-lock vessel inside' is the wordplay.
'land lock' becomes 'embay' (I can't explain this - if you can you should believe this answer much more).
'vessel' becomes 'SS' (prefix in ship names eg SS Great Britain).
'inside' means one lot of letters goes inside another.
'embay' placed around 'ss' is 'EMBASSY'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for embassy that I've seen before include "Consulate" , "senior diplomat's residence ..." , "Ambassador's residence" , "Office of an ambassador" , "Foreign Office" .)