intransitive verb
Definition: To smile widely, showing your teeth, usually because you are happy or amused.
Example: She couldn't help but grin when she heard the funny joke.
noun
Definition: A facial expression made by smiling broadly, often showing the teeth.
Example: She had a big grin on her face when she received the good news.
transitive verb
Definition: To smile broadly, often showing the teeth, usually as a sign of happiness or approval.
Example: She grinned when she saw her friend.