Indian seaport (6)
I believe the answer is:
madras
'indian seaport' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for madras that I've seen before include "Former name of Indian city and state" , "Indian city now recalled" , "Tamil Nadu capital; a hottish curry" , "Former name for Chennai" , "Old name for city now known as Chennai" .)