Large, first to lean over (4)
I believe the answer is:
list
'lean over' is the definition.
(thesaurus)
'large first' is the wordplay.
'large' becomes 'l'.
'first' becomes 'ist'.
'l'+'ist'='LIST'
'to' is the link.
(Other definitions for list that I've seen before include "Devoid of spirit or energy" , "Consecutive series of items" , "band > record" , "border" , "Desire" .)