Red Sea Commander (5)
I believe the answer is:
medoc
'red' is the definition.
(I've seen this before)
'sea commander' is the wordplay.
'sea' becomes 'med' (abbreviation of Mediterranean).
'commander' becomes 'oc' (I've seen this in other clues).
'med'+'oc'='MEDOC'
(Other definitions for medoc that I've seen before include "Wine-growing area" , "region of France" , "French red wine" , "French intoxicant" , "that's regularly drunk?" .)