Son has time to be a scholar (4)
I believe the answer is:
sage
'a scholar' is the definition.
(thesaurus)
'son has time' is the wordplay.
'son' becomes 's'.
'has' means one lot of letters go next to another.
'time' becomes 'age' (age is a kind of time**).
's'+'age'='SAGE'
'to be' is the link.
(Other definitions for sage that I've seen before include "Wise man - flavoursome plant" , "Seasoning for the wise one" , "Oracle; herb" , "Solon, for instance" , "Feature of herb garden" .)