Spend unwisely being depressed (4)
I believe the answer is:
blue
'being depressed' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for blue that I've seen before include "Sea colour" , "Sad - shade" , "Colour; squander" , "Terrible commotion?" , "Conservative > depressed" .)