Good argument to get bigger (4)
I believe the answer is:
grow
'get bigger' is the definition.
(I've seen this before)
'good argument' is the wordplay.
'good' becomes 'g' (abbreviation).
'argument' becomes 'row' (to row is to argue).
'g'+'row'='GROW'
'to' is the link.
(Other definitions for grow that I've seen before include "Get bigger" , "Mature" , "Multiply" , "Develop - propagate" , "Increase in size" .)