Shoot a regiment that's out of order (9)
I believe the answer is:
germinate
'shoot' is the definition.
(synonyms)
'a regiment that's out of order' is the wordplay.
'that's out of order' is an anagram indicator.
'a'+'regiment'='aregiment'
'aregiment' is an anagram of 'GERMINATE'.
(Other definitions for germinate that I've seen before include "Start to grow - a regiment (anag)" , "Mere giant (anag) - start to grow" , "Spring up" , "come to life" , "Sprout - develop" .)