Down current unseen in Egyptian port (3)
I believe the answer is:
sad
'down' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sad that I've seen before include "Unhappy or melancholy" , "Disconsolate" , "low" , "Tragic" , "Sorrowful, unhappy" .)