flightless

adj (of birds) not able to fly （指鸟）不会飞的.

flex, flexibility, flexible, flexibly, flexitime, flibbertigibbet, flick, flick-knife, flicker, flier, flier (also flyer), flies, flight, flight attendant, flight lieutenant, flight path, flight sergeant, flight simulator, flight-deck, flight-recorder, flighty, flimsily, flimsiness, flimsy, flinch, fling, flint, flintlock, flinty, flip, flip side, flip-flop, flippancy, flippant, flippantly, flipper, flipping, flirt, flirtation, flirtatious,