裹足不前
Fight shy of.
At a standstill.
Drag one's heels.

eg：The shy girl hung back and refused to participate in the contest.

中英俚语俗语来源：李斯 ·谏逐客书：“使天下之士，退而不敢西向，裹足不人秦。”

同义词：停滞不前 Get bogged down.
反义词：争先恐后 The devil take the hindmost.