With a girn that was like to rive his mouth, he twisted his nieve in the back of my hair, and off with me hanging by the cuff of the neck, like a kittling.
To "girn in a widdy" is to laugh or girn when a halter is round the neck--meaning that it is no joke to be placed in a difficult or dangerous position.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "girn" in a variety of sentences. We hope that you will now be able to make sentences using this word.