1. Verb. Exercising the art of masturbation 2. Verb. To create an orgasm simulating another sexual partner with the hand or other masturbating aids (e.g. fleshlight, hand, dildo)
3.Noun. An asshole, homo, or otherwise retard who's by calling them a jack-off is saying that they shouldn't have been born and was a waste of sperm which is a jack-off
4.Noun. A waste of sperm produced by the art of masturbation
Tom is a porn addict, therefore he likes to jack-off.
Tom jacks off in public for everyone to view therefore he is a jack-off.
Noun: A person, either male or female, who wastes a car salesperson's time when that salesperson could be doing something either more constructive or entertaining. Used as the strongest epithet for a non-buyer in the retail automotive industry.
"Would you believe that fucking Jack-off had Johnny test drive him in three cars then left without so much as a writeup!!" Also, "Beat it, you Jack-off!" Frequently shortened to "Jack", such as "What a Jack!"