Unusually dire prospects for group loyalty (6,2,5)
I believe the answer is:
esprit de corps
'group loyalty' is the definition.
(I've seen this before)
'unusually dire prospects' is the wordplay.
'unusually' indicates an anagram.
'dire'+'prospects'='direprospects'
'direprospects' anagrammed gives 'ESPRIT DE CORPS'.
'for' is the link.
(Other definitions for esprit de corps that I've seen before include "Pride within a group" , "camaraderie" , "Group's mutual loyalty" , "Collective feeling of pride" , "loyalty to organisation" .)