The noun grin has 1 sense (first 1 from tagged texts)
1. (6) smile, smiling, grin, grinning -- (a facial expression characterized by turning up the corners of the mouth; usually shows pleasure or amusement)
Overview of verb grin
The verb grin has 1 sense (first 1 from tagged texts)
1. (18) grin -- (to draw back the lips and reveal the teeth, in a smile, grimace, or snarl)