Great, worth rewriting to get advance (6)
I believe the answer is:
growth
'advance' is the definition.
(thesaurus)
'great worth rewriting' is the wordplay.
'great' becomes 'g' (abbreviation in place names).
'rewriting' indicates anagramming the letters.
'worth' with letters rearranged gives 'rowth'.
'g'+'rowth'='GROWTH'
'to get' acts as a link.
(Other definitions for growth that I've seen before include "Process of increase" , "Process of enlargement" , "Augmentation" , "Tumour - enlargement" , "Process of development" .)