We use the word "jerk" as a noun when describing a person whose behavior is not polite. The person is rude. This is a popular word in the United States. It’s usually used for men.
Everyone got mad at Gerardo because he was being such a jerk towards the waitress.
Some jerk threw all the trash that was in his car on the ground in the parking lot.
The jerk driving behind me got too close with his car and hit my rear bumper when I suddenly stopped.
Amanda always seems to go out with guys who are jerks. Why can’t she find someone who’s nice?
Tom hates talking to his boss because his boss is a jerk.
What a jerk!
You can also use "jerk" as a verb. In this case, it means a sudden motion:
simple
past
past participle
jerk
jerked
jerked
The car jerked forward when the driver put it into first gear.
The little boy jerked something out of his sister’s hands.
Don’t jerk your fishing pole too hard if you think a fish has taken your bait.
The word "jerky" is an adjective:
That was a jerky thing to do. What did he do that?