French are blocking the current proposition (6)
I believe the answer is:
thesis
'proposition' is the definition.
(thesis is a kind of proposition)
'french are blocking the current' is the wordplay.
'french are' becomes 'es' ('are' in French).
'blocking' indicates putting letters inside.
'the current' becomes 'this' (eg this year means the current year).
'es' inserted inside 'this' is 'THESIS'.
(Other definitions for thesis that I've seen before include "Dissertation - idea" , "student's work" , "Dissertation based on research" , "writing following research" , "Essay putting forward a particular view" .)