Can you crack this tricky crossword clue?

The answer to the crossword question “Friendly — or sly — look is GRIN” is simply GRIN. A GRIN is a facial expression that is commonly associated with happiness, friendliness, and amusement. However, it can also be used in a sly or mischievous manner depending on the context it is used in. A GRIN is often characterized by the turning up of the corners of the mouth, and may or may not involve the baring of teeth. Overall, a GRIN is a versatile expression that can convey various emotions and intentions depending on how it is used.