Halfjack

1. to get any current work or job half done.

2. someone who only finishes half their objective.
“this car has been half built, looks like we got a halfjack on our hands.”

or

“d-mn! he only finished half the fence! what a halfjack!”
4 more definitions
you get so uninterested in masturbating, that you stop before you c-m.
peter: dude! i was so baked last night, i was whacking off and got bored and stopped.

paul: just a half-jack then?
the process of exciting male genitalia until it is partially erect in order to help the refractory period after getting the first “easy” -rg-sm out of the way.
joe half-jacked so that later when he has s-x with jennifer wh-r-ton he would be able to reduce the time between s-xual excursions.
1. one who never goes more then halfway on anything

2. a boyfriend never planning a date and leaving all the work to his girlfriend and more commonly referred to as a jack-ss

3. one who has winterfresh on a daily basis and swallows

ex 1. paul never planned anything with his girlfriend so he is a halfjack / jack-ss
ex 2. paul likes to swallow winterfresh
“half jack” refers to a person who is gender confused, and possibly considering s-x change surgery. a person who either feels that they are of the wrong gender, or that they are half male and half female.
mary was really into tom at the party last night, but she wasnt aware that he’s “half jack” and had no interest in her.