futile

a.无用的, 无效的

furtively, furtiveness, fury, furze, fuse, fuse wire, fuse-box, fuselage, fusible, fusilier, fusillade, fusion, fuss, fussily, fussiness, fusspot, fussy, fustian, fustiness, fusty, futility, future, futures, futurism, futurist, futuristic, futurity, fuzz, fuzzily, fuzziness, fuzzy, fwd, g, G, g, G-string, gab, gabardine (also gaberdine), gabble, gable, gabled,