http://en.wikipedia.org/wiki/Mustang_(military_officer)
Mustang (military officer)
A Mustang is United States Military slang for a commissioned officer who began his or her career as an enlisted service member. Mustangs are older and more experienced than their peers-in-grade who earned their commissions from one of the service academies (such as the United States Military Academy, United States Air Force Academy, or United States Naval Academy), Officer Candidate School, or the Reserve Officer Training Corps. During the Vietnam War, however, when some Army warrant officer pilots were offered a direct commission to 2nd or 1st Lieutenant, they were usually younger than 25 at the time of commission.
A United States Navy mustang can be a Chief Warrant Officer, a Limited Duty Officer, a Staff Officer, a Restricted Line Officer or an Unrestricted Line Officer, depending on their particular situation.
The original definition of a mustang was a military officer who had earned a battlefield commission; they were especially prevalent during World War II and the Korean War. Such notables include Audie Murphy (World War II) and David Hackworth (Korean War).
A mustang is currently defined[citation needed] by a continuity in military service from enlisted to officer (i.e., no break in military service). Being a slang term, there is no precise definition or set of criteria to determine which officers can properly be called a "mustang"; however, generally accepted as mustangs are those who earned a Good Conduct Medal, or have completed 4 years of enlisted service prior to earning their commission.
The term "Mustang" is a relatively modern term, originating either just prior to, or during World War II. It is believed to be a naval term, although other service's officers are beginning to be described as mustangs.
It literally refers to the mustang horse, which is a wild animal and therefore not a thoroughbred. A mustang, after being captured, can be tamed and saddle broken but it always has a bit of wild streak, and can periodically revert to its old ways unexpectedly and therefore the owner needs to keep an eye on it at all times.
By the same token, however, since a mustang was formerly a wild and free animal, it may very well be smarter, more capable and have a better survival instinct than thoroughbreds.
