overdraft n.

word-forming element meaning variously "above; highest; across; higher in power or authority; too much; above normal; outer; beyond in time, too long," from Old English ofer (from PIE root *uper "over"). Over and its Germanic relations were widely used as prefixes, and sometimes could be used with negative force. This is rare in Modern English, but compare Gothic ufarmunnon "to forget," ufar-swaran "to swear falsely;" Old English ofercræft "fraud."

In some of its uses, moreover, over is a movable element, which can be prefixed at will to almost any verb or adjective of suitable sense, as freely as an adjective can be placed before a substantive or an adverb before an adjective. [OED]

Among the old words not now existing are Old English oferlufu (Middle English oferlufe), literally "over-love," hence "excessive or immoderate love." Over- in Middle English also could carry a sense of "too little, below normal," as in over-lyght "of too little weight" (c. 1400), overlitel "too small" (mid-14c.), oversmall (mid-13c.), overshort, etc.

c. 1500, a spelling variant of draught (q.v.) to reflect change in pronunciation. By the end of the 19c. it was the established form in the military, commercial, and many technical sentences, and it is now almost universal in American English as conforming to the pronunciation.

The meaning "rough copy of a writing" (something "drawn") is attested from 14c.; that of "preliminary sketch from which a final copy is made" is from 1520s; that of "flow of a current of air" is from c. 1770. Of beer from the 1830s, in reference to the method of "drawing" it from the cask. Sense in bank draft is from 1745. The meaning "a drawing off a group for special duty" is from 1703, in U.S. especially of military service; the verb in this sense first recorded 1714. Related: Drafted; drafting.