Have attire for ball that doesn't start (3)
I believe the answer is:
own
'have' is the definition.
(to have something is to own it)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for own that I've seen before include "Private" , "Have in one's possession" , "Posses" , "Keep" , "Be in legal possession of (3)" .)