colours ... are associated with cheerfulness .. dolours is opposite
DOL(SOUNDS LIKE DULL)..and when are you DULL, when you are feeling SORRY for something.
DULL ARE US
Many religious points of view considered money as the source of human sorrows. So dolorous from "dollars" so means sorrowful.
Link it with 'dollar'
DOLO(sway)+ROZ(evereday)....it's painful to sway like grass everyday without any reason....
The prices of DOLOR($) in Iran are dolorous.