Sarge's boss

LOOIE

This military rank is one step above a second lieutenant and often shortened in casual speech; think of a junior officer in charge of a platoon.

"Sarge" is military slang for a sergeant, and "Sarge's boss" refers to the next rank up in the U.S. Army. The answer "LOOIE" is a casual term for a lieutenant, pronounced "loo-ee," which is the officer who typically outranks a sergeant. The clue plays on military nicknames, where "looiie" is a phonetic spelling of how soldiers often say "lieutenant" in conversation.