Very good, very good, OK (2-2)
I believe the answer is:
so-so
'ok' is the definition.
(I've seen this before)
'very good very good' is the wordplay.
'very good' becomes 'so' (as in the adjectival form 'just so!').
'very good' becomes 'so' (as in the adjectival form 'just so!').
'so'+'so'='SO-SO'
(Other definitions for so-so that I've seen before include "Rather middling" , "Informally, only moderately good or well" , "Only moderately good in repetitive way" , "Neither good nor bad" , "'Passable, middling (2-2)'" .)