quail before (someone or something)
To tremble with fear before someone or something; to cower or whimper in the face of someone or something. The headmistress at my old school was so menacing—we all quailed before her whenever we were called to her office. The people of this country will quail before the might of our army.
quail before someone or something
to cower before or at the threat of someone or something. The students quailed before the angry principal. They quailed before the thought of punishment.