I married many a European to be protected (6)
I believe the answer is:
immune
'be protected' is the definition.
(I've seen this before)
'i married many a european' is the wordplay.
'married' becomes 'm'.
'many' becomes 'm'.
'a european' becomes 'une' ('a' translated into French).
'i'+'m'+'m'+'une'='IMMUNE'
'to' is the link.
(Other definitions for immune that I've seen before include "Not liable to, perhaps disease" , "Exempt, secured against" , "Exempt, invulnerable" , "Exempt or protected" , "Not subject or liable to" .)