Definition of shavetail in US English:

shavetail

noun

US
military slang, derogatory
  • 1A newly commissioned officer, especially a second lieutenant.

    • ‘The shavetail saluted crisply and started prodding the crowd into a semblance of order.’
    • ‘This is no old soldier's tale, but a reflection by a true ‘shavetail’ on his experiences in the profession of arms.’
    • ‘RA ranks within the 2nd Training Regiment at Fort Dix boasted just one colonel, one lieutenant colonel, a first lieutenant and three shavetails.’
    1. 1.1informal An inexperienced person.
      as modifier ‘the shavetail Assistant District Attorney’
      • ‘While you and the shavetail here were shooting it out with Fine and Amos, I grabbed the doc.’

Origin

Figuratively, from the early sense ‘untrained pack animal’ (identified by a shaven tail).

Pronunciation

shavetail

/ˈSHāvˌtāl/