Yearn for years (4)
I believe the answer is:
long
I believe this is a double definition.
'yearn' is the first definition.
(I know that yearn is a more specific form of long)
'years' is the second definition.
(thesaurus)
'for' is the link.
(Other definitions for long that I've seen before include "Really want" , "Sustained" , "summer break?" , "bought in advance" , "hunger" .)