schlagfertig

Etymology
Mid-17th century, equivalent to. Probably a. For this speak the slightly earlier attestion (1625), the invariably nautical context of the earliest German attestations, and the fact that means “battle”. (The proper German form would thus be, which makes more sense semantically and is indeed attested.)

Adjective

 * 1)  ready and capable to strike, attack
 * 2)  quick-witted, good at repartee
 * 3)  prompt and witty
 * 1)  prompt and witty