Veterans formed square (3-9)
I believe the answer is:
old-fashioned
'square' is the definition.
(I've seen this before)
'veterans formed' is the wordplay.
'veterans' becomes 'old' (many veterans are old people).
'formed' becomes 'fashioned'.
'old'+'fashioned'='OLD-FASHIONED'
(Other definitions for old-fashioned that I've seen before include "Outmoded - 1 down" , "square" , "Pass" , "Passe; whisky cocktail" , "Demode" .)