Essential condition ( Latin ) (4,3,3)
I believe the answer is:
sine qua non
(Other definitions for sine qua non that I've seen before include "Must" , "A vital qualification" , "Indispensable condition" , "Essential condition" .)
I believe the answer is:
sine qua non
(Other definitions for sine qua non that I've seen before include "Must" , "A vital qualification" , "Indispensable condition" , "Essential condition" .)