frivolous

adj. 轻佻的,妄动的,琐碎的 (n. frivolity)

frightening, frighteningly, frightful, frightfully, frigid, frigidity, frigidly, frill, frilled, frilly, fringe, fringe benefit, frippery, Frisbee, frisk, friskily, frisky, frisson, fritter, frivolity, frivolously, frizz, frizzle, frizzy, fro, frock, frock coat, frock-coat, frog, frog-march, frog-spawn, frogman, frolic, frolicsome, from, from memory, from now on, from side to side, from then on, from time to time,