non-commissioned (adj.)

a prefix used freely in English and meaning "not, lack of," or "sham," giving a negative sense to any word, 14c., from Anglo-French noun-, from Old French non-, from Latin non "not, by no means, not at all, not a," from Old Latin noenum "not one" (*ne oinom, from PIE root *ne- "not" + PIE root *oi-no- "one, unique"). In some cases perhaps from Middle English non "not" (adj.), from Old English nan (see not). "It differs from un- in that it denotes mere negation or absence of the thing or quality, while un- often denotes the opposite of the thing or quality" [Century Dictionary].

1660s, "empower or authorize by commission," from commission (n.). In the naval sense, of persons, "be given the rank of an officer (by commission from authority)," from 1793; of a ship, "to be transferred from the naval yard and placed in the command of the officer put in charge of it," 1796. Related: Commissioned; commissioning.

also noncom, by 1817, short for non-commissioned(officer).

The "non-coms" — non-commissioned, meaning, not non compos; though evil-minded high privates declare it might well mean that — have assigned to them an upper cabin, with staterooms, over the quarters of the officers, in the after-part of the ship. [James K. Hosmer, "The Color-Guard," Boston, 1864]