Calm — ocean (7)
I believe the answer is:
pacific
I believe this clue is a double definition.
'calm' is the first definition.
(I've seen this before)
'ocean' is the second definition.
(I know that Pacific is a ocean)
(Other definitions for pacific that I've seen before include "Peaceable" , "Large ocean" , "Non-combatant" , "steam locomotive?" , "Peacemaking" .)