In suspense as a horse eats nothing (4)
I believe the answer is:
agog
'in suspense' is the definition.
(I've seen this in another clue)
'a horse eats nothing' is the wordplay.
'horse' becomes 'gg' (geegee or GG is a childish term for a horse).
'eats' indicates putting letters inside.
'nothing' becomes 'O' (looks like zero - 0).
'gg' placed around 'o' is 'gog'.
'a'+'gog'='AGOG'
'as' is the link.
(Other definitions for agog that I've seen before include "Very eager (to hear/see)" , "Expectant and wide-eyed" , "Eager - in suspense" , "Very eager (to see/hear)" , "Wide-eyed and surprised" .)