A key declaration gets enthusiastic approval (7)
I believe the answer is:
acclaim
'enthusiastic approval' is the definition.
(I've seen this before)
'a key declaration' is the wordplay.
'key' becomes 'c' (I've seen this in other clues).
'declaration' becomes 'claim' (claim is a kind of declaration).
'a'+'c'+'claim'='ACCLAIM'
'gets' is the link.
(Other definitions for acclaim that I've seen before include "Credit" , "Welcome with shouts of approval" , "Cheer" , "Extol" , "Welcome enthusiastically" .)