This idiom is used to mean overrating(估计过高) oneself and trying to do what is beyond one's ability. The result can be nothing but failure.
春秋时,卫灵公请颜阖为太子之师,颜阖知蒯瞶为人阴险凶残,欲改其恶习,导之正途,但恐遭杀身之祸,而问於蘧伯玉。伯玉语喻之曰:“螳螂奋其臂以挡车轮,其不知否能胜任也,徒取灭亡耳。不可高估本身之力,而为太子之师。若自持己见,必遭太子之嫌。是以务必小心从事。”颜阖从之,婉拒卫灵公之请。
亦作“螳臂挡车”或作“螳臂当辕”。