gunny
A nickname for a senior ranking non-commissioned officer in the United States Marine Corps with the pay-grade of E7 and the rank of Gunnery Sergeant. This nickname's usage, often used as a term of respect, is determined by the GSgt.
LCorporal: Hey, gunny?
GSgt: Yeah?
LCorporal: Pyle took a **** in the M998. AGAIN!
GSgt: Picks up Kabar knife