c. 1200, recoilen, transitive, "force back, drive back, beat back" (senses now archaic or obsolete); c. 1300, intransitive, "shrink back, retreat," from Old French reculer "to go back, give way, recede, retreat" (12c.), from Vulgar Latin *reculare, from Latin re- "back" (see re-) + culus "backside, bottom, fundament" (see tutu). The sense of "spring back" (as a firearm when discharged) is attested from 1520s. Related: Recoiled; recoiling.
c. 1300, "a retreat, a drawing back" (a sense now obsolete), from Old French recul "recoil, backward movement, retreat," from reculer (see recoil (v.)). Meaning "back-kick of a firearm or piece of ordnance when discharged" is from 1570s.