Highly excited (4)
I believe the answer is:
agog
'highly excited' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for agog that I've seen before include "Eagerly expectant" , "Impatient" , "Wide-eyed and amazed" , "Mouth open" , "Very eager (to hear/see)" .)