cowardly

cowardly
adj (derog 贬) lacking courage; of or like a coward 胆小的; 怯懦的; （似）胆小鬼的
    cowardly lies, behaviour, actions 怯懦的谎言、 行为、 举动
    It was cowardly of you not to admit your mistake. 你不承认错误就不是好样儿的.

牛津英汉双解词典