Blue bean? (4)
I believe the answer is:
navy
This clue is a double definition.
'blue' is the first definition.
(shade of blue)
'bean?' is the second definition.
(navy bean is a kind of bean)
(Other definitions for navy that I've seen before include "Armed force" , "Fleet of ships" , "military arm" , "Ships-of-war" , "Fleet - blue" .)