Soft shade (4)
I believe the answer is:
aqua
'soft shade' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aqua that I've seen before include "which supports boats?" , "-- fortis, 'strong water'" , "- Regia; - fortis" , "- - Libra" , "Hue" .)