Command corrupt peers' exit (9)
I believe the answer is:
expertise
'command' is the definition.
(thesaurus)
'corrupt peers' exit' is the wordplay.
'corrupt' indicates an anagram.
'peers'+'exit'='peersexit'
'peersexit' with letters rearranged gives 'EXPERTISE'.
(Other definitions for expertise that I've seen before include "Craft" , "Mastery, proficiency" , "Pert sex, i.e. could become skilled knowledge" , "Adroitness" , "Skill or knowledge in a particular field" .)