faithlessly 

英汉解释

adv. 靠不住地；不忠实地

同义词

r. false，traitorously，treacherously，treasonably

参考例句

1. He faithlessly forsook his friends in their hour of need.
在最需要的时刻他背信弃义地抛弃朋友。
2. Our fathers acted faithlessly and did evil in the eyes of the LORD, our God. They abandoned him, turned away their faces from the LORD'S dwelling, and turned their backs on him.
因为我们的祖先犯了罪，行了上主我们的天主视为不悦的事，离弃了他，并转脸不顾上主的居所，所以背相向；

英英解释

adv.
  1. in a disloyal and faithless manner

网络释义

faithlessly
不忠实地; 不贞地;
faithlessly perfidiously unfaithfully
不忠实地;