1: throwing up, puking
2: to rid your body of pretty much everything it can, usually in the form of post party vomit or shit.
"man! that made me sick, i totally had to go out back and jettison!"
"i partied so hard, i had spent an hour afterwards jettisoning everything!"
1. To leave a location.
2. To quickly depart from a location.
see also: jet
"I gotta get up early tomarrow so I'm about to jettison."