Nothing going on? (8,4)
I believe the answer is:
birthday suit
'nothing' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for birthday suit that I've seen before include "Invisible threads?" , "Invisible attire?" , "Nothing to wear?" , "State of total nakedness" , "Invisible outfit?" .)