When you grin, you smile. You're likely to grin when your sister tells you a particularly funny knock-knock joke.

There's some disagreement about the difference between a grin and a smile — some define a grin as a broad smile that exposes your teeth, but others consider a grin to be a smile with lips tightly closed. Either way, a grin usually expresses amusement, although it sometimes has a mischievous or sly implication: "No one confessed to letting the rabbit loose in the classroom, but one student's grin gave her away."

Definitions of grin

v to draw back the lips and reveal the teeth, in a smile, grimace, or snarl

Type of:
change one's facial expression by spreading the lips, often to signal pleasure

n a facial expression characterized by turning up the corners of the mouth; usually shows pleasure or amusement

grinning, smile, smiling
a silly self-conscious smile
a smile expressing smugness or scorn instead of pleasure
Type of:
facial expression, facial gesture
a gesture executed with the facial muscles

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