Irreverence of Zulu warriors yet to be trained (7)
I believe the answer is:
impiety
'irreverence' is the definition.
(impiety is a kind of irreverence)
'zulu warriors yet to be trained' is the wordplay.
'zulu warriors' becomes 'impi' (I've seen this before).
'to be trained' is an anagram indicator (train can mean to shape or manipulate).
'yet' anagrammed gives 'ety'.
'impi'+'ety'='IMPIETY'
'of' is the link.
(Other definitions for impiety that I've seen before include "Lack of reverence" , "sacrilege" , "godlessness" , "Irreligion" , "Irreverence, profanity" .)