Vessel returning to dock in low country (6)
I believe the answer is:
monaco
'country' is the definition.
(I know that Monaco is a country)
'vessel returning to dock in low' is the wordplay.
'vessel' becomes 'can' (type of container).
'returning' says the letters should be written in reverse.
'to dock in' indicates putting letters inside.
'low' becomes 'moo' (both can mean to make the noise of a cow).
'can' written backwards gives 'nac'.
'nac' going inside 'moo' is 'MONACO'.
(Other definitions for monaco that I've seen before include "Grand Prix street circuit" , "Constitutional monarchy on the French Riviera" , "Small European country" , "Home of the Grimaldis" , "Mediterranean principality" .)