Old English *tyltan "to be unsteady," from tealt "unsteady," from Proto-Germanic *taltaz (cf. Old Norse tyllast "to trip," Swedish tulta "to waddle," Norwegian tylta "to walk on tip-toe," Middle Dutch touteren "to swing"). Meaning "to cause to lean, tip, slope" (1590s) is from sense of "push or fall over." Intransitive sense first recorded 1620s. Related: Tilted; tilting.
"a joust, a combat," 1510s, perhaps from tilt (v.) on the notion of "to lean" into an attack, but the word originally seems to have been the name of the barrier which separated the combatants, which suggests connection with tilt in an earlier meaning "covering of coarse cloth, an awning" (mid-15c.), which is probably from tilt (v.), but perhaps related to or influenced by tent, or it may be from a Germanic source akin to Old English beteldan "to cover." The verb is recorded from 1590s. Hence, also full tilt (c.1600).
"condition of being tilted," 1837, from tilt (v.).