Eager to go inside (4)
I believe the answer is:
agog
'eager' is the definition.
(I've seen this before)
'to go inside' is the wordplay.
'to' becomes 'ag' (I am not sure about this - if you are sure you should believe this answer much more).
'inside' indicates putting letters inside.
'ag' going around 'go' is 'AGOG'.
Can you help me to learn more?
(Other definitions for agog that I've seen before include "Eager - in suspense" , "with eyes on stalks" , "State of wide-eyed wonder" , "In state of wide-eyed expectancy" , "Eagerly awaiting" .)