虫むしも殺ころさぬ

expression, pre-noun adjectival

innocent-looking; wouldn't hurt a fly

Describes someone who appears so gentle and harmless that they seem incapable of even killing an insect. Often used with a hint of irony or to emphasize a deceptively meek appearance.

• 彼かの女じょは虫むしも殺ころさぬ顔かおで、実じつはとてもしたたかだ。

  She looks as though she wouldn't hurt a fly, but she's actually quite shrewd.

• 虫むしも殺ころさぬような笑え顔がおで近ちかづいてきた。

  He approached with an innocent-looking smile.