acute, adamant, adamantine, airy, alternate, alternating, anon, apace, astute, bouncing, brainy, brawny, briefly, bright, briskly, brogue, browse, burly, callous, change, changeable, choppy, clever, convertible, cute, directly, erelong, erratic, expedite, expeditious, extravagant, fast, fickle, firm, firmed, flighty, floating, fluky, forte, frivolous, giddy, glibly, gutsy, hale, hard, hard-boiled, hard-core, hardboiled, hardcore, hardy, hastily, hasty, heady, heavy, heedless, hefty, husky, improvident, inane, incisive, inconsiderate, insouciant, keen, keener, landed, light, light-footed, light-minded, luminous, lusty, mercurial, modifiable, moodiness, mutable, nappy, nervy, nigh, nimble, oftentimes, penetrating, perspicacious, potent, powerful, presently, presto, prompt,
promptly, pronto, quick, quick-witted, quicker, quickly, rank, rapid, rapidly, readily, ready, reckless, repeatedly, rigid, robust, rooted, rush, sagacious, sharp, sharp-witted, shifty, shortly, shrewd, skim, smart, smoothly, snappy, solid, solid-state, soon, speed, speedily, speedy, spry, stable, stalwart, stanch, stark, steadfast, steady, stiff, stout, strong, sturdy, supple, swift, swiftly, swimmingly, thoughtless, torrential, tough, variable, versatile, vicissitudes, virile, virtual, volatile, witty