Ship docks in empty port over here (4)
I believe the answer is:
psst
'over here' is the definition.
(I've seen this before)
'ship docks in empty port' is the wordplay.
I cannot quite understand how this works, but
'ship' could be 'ss' (prefix in ship names eg SS Great Britain) and 'ss' is located in the answer.
'port' could be 'pt' (abbreviation) and 'pt' is found in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for psst that I've seen before include "Here's a secret" , "Sound to call quietly" , "Sibilant interjection to call attention" , "Sound of call to hear a secret" , "Don't tell anyone" .)