In excited eagerness (4)
I believe the answer is:
agog
'in excited eagerness' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for agog that I've seen before include "Eager or curious" , "Wide-eyed and fascinated" , "Interested, excited and eager to know more" , "with eyes on stalks" , "Open-mouthed" .)