Free entry of one into Grexit arrangement has advantage, initially (2,6)
I believe the answer is:
ex gratia
'free' is the definition.
('ex gratia' is 'free' in Latin)
'entry of one into grexit arrangement has advantage initially' is the wordplay.
'entry of one' becomes 'a' (I am not sure about this - if you are sure you should believe this answer much more).
'into' is an insertion indicator.
'arrangement' indicates anagramming the letters.
'has' says to put letters next to each other.
'initially' indicates taking the first letters.
The initial letter of 'advantage' is 'a'.
'grexit' with letters rearranged gives '[grexit]'.
'[grexit]'+'a'='exgrtia'
'a' going inside 'exgrtia' is 'EX GRATIA'.
Can you help me to learn more?
(Other definitions for ex gratia that I've seen before include "I tax gear given as favour, no charge" , "Done as a favour, not as obligation" , "(Done) as a favour (Latin)" , "Payment as a favour, not as an obligation" , "Given as concession without legal compulsion" .)