In the past, good to be expectant (4)
I believe the answer is:
agog
'be expectant' is the definition.
(thesaurus)
'in the past good' is the wordplay.
'in the past' becomes 'ago' ('ago' can be a synonym of 'in the past').
'good' becomes 'g' (abbreviation).
'ago'+'g'='AGOG'
'to' is the link.
(Other definitions for agog that I've seen before include "In excited eagerness" , "Eagerly excited" , "Bug-eyed" , "Eagerly awaiting" , "Very curious to hear" .)