Definition of jerks:
(n) :
A sudden, often uncontrolled movement, especially of the human body.
(n) :
A quick pull on something.
(n) :
(originally Canada, US, slang, derogatory) A person with unlikable or obnoxious qualities and behavior, typically mean, self-centered, or disagreeable.
(n) :
(US, slang, derogatory) A stupid person; an idiot or fool.
(n) :
(weightlifting) A lift in which the weight is taken with a quick motion from shoulder height to a position above the head with arms fully extended and held there for a brief time.
(n) :
(slang) Masturbation.