咬人狗兒不露齒 [ㄧㄠˇ ㄖㄣˊ ㄍㄡˇ ˙ㄦ ㄅㄨˋ ㄌㄨˋ ㄔˇ; yao3 ren2 gou3 r5 bu4 lu4 chi3] lit. the dog that bites does not show its fangs (idiom) fig. You can't tell the really dangerous enemy from his external appearance. ◄ ►