Silly originally, time to get wise (4)
I believe the answer is:
sage
'wise' is the definition.
(similar in meaning)
'silly originally time' is the wordplay.
'originally' suggests taking the first letters.
'time' becomes 'age' (age is a kind of time).
The initial letter of 'silly' is 's'.
's'+'age'='SAGE'
'to get' is the link.
(Other definitions for sage that I've seen before include "A herb or a guru" , "Herb; wise person" , "Fragrant herb or wise man" , "Herb used in cooking" , "Clary" .)