1. newly commissioned military officers, especially second lieutenants
Usage: military slang; informal
2. young, untrained mules or horses
Usage: historical; informal

Examples

• The sergeant had little patience for the shavetails fresh out of officer training.
• Three shavetails reported to the base yesterday for their first assignment.
• The old colonel remembered when he was just another shavetail learning the ropes.
• In the Old West, shavetails were often difficult to handle on long journeys.
• The army used shavetails for pack duty until they could be properly trained.
• These shavetails need months of training before they’re ready for combat.