Of key importance (7)
I believe the answer is:
pivotal
(Other definitions for pivotal that I've seen before include "Of central importance" , "Key" , "Crucial, critical" , "Of crucial importance" , "Crucially important" .)
I believe the answer is:
pivotal
(Other definitions for pivotal that I've seen before include "Of central importance" , "Key" , "Crucial, critical" , "Of crucial importance" , "Crucially important" .)