Sad, like some eyes (4)
I believe the answer is:
blue
I believe this clue is a double definition.
'sad' is the first definition.
(similar in meaning)
'like some eyes' is the second definition.
(eyes can be blue)
(Other definitions for blue that I've seen before include "ball at snooker" , "Sunny sky or low spirits" , "Sad, melancholy" , "Naughty < sportsman" , "adult" .)