snigger
/ˈsnɪgə(r); `snɪɡɚ/ n
half-suppressed unpleasantlaugh (esp at sth improper or at another's misfortune) 窃笑, 暗笑（尤指笑某事物不当或他人不幸）
Her shabby appearance drew sniggers from the guests. 她样子寒酸, 客人不禁暗自发笑. snigger, v [I, Ipr]
~ (at sb/sth) laugh in this way 窃笑; 暗笑
superior people who sniggered at her foreign accent 暗笑她有外国腔调的那些自以为比她强的人. =>Usage at giggle 用法见 giggle.