v. phr. To touch or bother, even a little. Used in negative, interrogative, and conditional sentences. Don't you dare lay a finger on the vase! Suppose Billy fakes his brother with him; wilt the mean, tough boy down the street dare lay a finger on him? If you so much as lay a finger on my boy, I'll call the police.
Compare: LAY HANDS ON, PUT ONE'S FINGER ON.