C2idiominformalfood
butter wouldn't melt in your mouth
USUK
looking very innocent and well behaved, though you are not
Often 'look as if butter wouldn't melt in your mouth' with a hint of doubt. British and slightly teasing.
In context
The little boy looked as if butter wouldn't melt in his mouth, but he had drawn on every wall.
She acts as though butter wouldn't melt in her mouth, yet she started the rumour.
More idioms about food
- a bad appleone bad person who has a bad effect on the rest of a group
- a couch potatoa person who spends a lot of time sitting and watching TV instead of being active
- a different kettle of fisha completely different situation from the one just mentioned
- a finger in every pieinvolved in many different activities, often to get power
- a meal ticketa person or thing that someone uses as a source of money or support