Out at night, more so than usual - it's what she does not having met handsome prince yet (9)
I believe the answer is:
oversleep
'out' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'night more so than usual it's what she does not having met handsome prince yet' is the wordplay.
I cannot really understand how this works, but
'more' could be 'over' (I've seen this before) and 'over' is present in the answer.
'she' could be 'lee' and 'lee' is found in the answer.
'prince' could be 'p' and 'p' is found within the answer.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'at' is the link.
Can you help me to learn more?
(Other definitions for oversleep that I've seen before include "not be able to get up" , "ignore call to be roused" , "Fail to hear alarm clock?" , "Wake too late" , "Get up too late" .)