shavetail
Concise Oxford English Dictionary © 2008 Oxford University Press:
shavetail/ˈʃeɪvteɪl/
▶noun US military slang, often derogatory a newly commissioned officer.
■ informal an inexperienced person.
– origin from the early sense ‘untrained pack animal’ (identified by a shaven tail).
'shavetail' also found in these Oxford entries:

