vain

a.徒劳的；空虚的；自负的

vacillation, vacuity, vacuous, vacuously, vacuousness, vacuum, vacuum cleaner, vacuum pump, vacuum tube (US) (Brit radio valve), vacuum-packed, vade-mecum, vagabond, vagary, vagina, vaginal, vagrancy, vagrant, vague, vaguely, vagueness, vainglorious, vainglory, vainly, vainness, valance, vale, valediction, valedictorian, valedictory, valence, valency, valentine, Valentine's Day, valerian, valet, valetudinarian, valian, valiant, valiantly, valid,