The term 'PRIVATE's Boss' can be summarized by two crossword solutions: Sergeant (8 letters) and Sarge (5 letters). A Sergeant is a military rank, typically the lowest non-commissioned officer rank in the army. Sergeants are responsible for leading small groups of soldiers and enforcing orders from higher ranking officers. Sarge is an informal term for Sergeant, often used in the military as a nickname or term of endearment.