Downshine
The word "downshine" is normally used in unsatisfactory situations. It can be used to describe or express disappointment. This term is a word to describe negativity or failure. The opposite of "downshine" is "updull" which in rare cases can be referred to as a "UD"
"That party last night was SUCH a downshine!"
"God Stacey stop being such a downshine!"
let-down
"God Stacey stop being such a downshine!"
let-down