Made for a sea? (6)
I believe the answer is:
formed
'made' is the definition.
('form' can be a synonym of 'make')
'for a sea?' is the wordplay.
'a sea?' becomes 'med' (short for Mediterranean).
'for'+'med'='FORMED'
(Other definitions for formed that I've seen before include "Shaped" , "Moulded or constructed" , "Made" , "Gave shape to" .)