Replacements for warships (4)
I believe the answer is:
subs
This clue might be a double definition.
'replacements' is the first definition.
Although both the answer and definition are plural nouns, I cannot understand how they can define each other.
'warships' is the second definition.
(sub is a kind of warship)
'for' is the link.
Can you help me to learn more?
(Other definitions for subs that I've seen before include "Players in reserve" , "vehicles" , "Reserves at football (sl.)" , "Advance payments" , "Underwater vessels (abbr)" .)