不知天高地厚 [ㄅㄨˋ ㄓ ㄊㄧㄢ ㄍㄠ ㄉㄧˋ ㄏㄡˋ; bu4 zhi1 tian1 gao1 di4 hou4] not to know the immensity of heaven and earth an exaggerated opinion of one's own abilities ◄ ►