Overexcited from honeymoon: young princess enjoyed romance, initially (5)
I believe the answer is:
hyper
'overexcited' is the definition.
(I've seen this before)
'honeymoon young princess enjoyed romance initially' is the wordplay.
'initially' says to take the initial letters.
The first letters of 'honeymoon young princess enjoyed romance' is 'HYPER'.
'from' acts as a link.
(Other definitions for hyper that I've seen before include "Overexcited" , "Over-stimulated" , "Abnormally active" , "More excitable than normal" , "Slang adjective for over-active or highly-strung" .)